The Complete Guide to Seiko Mod Watch Movements: NH35, NH36, NH34, NH72, Miyota 8285, and VK63 — Including Common Problems and Fixes

If you've spent any time researching Seiko mod watches, you've encountered a list of alphanumeric codes that look more like aircraft registration numbers than watch specifications. NH35. NH34. NH72. VK63. They appear in product listings, forum discussions, and YouTube reviews usually without much explanation of what they actually mean or why they matter.

They matter a lot.

The movement inside a watch is its engine. Every other component the case, the dial, the bracelet, the crystal is built around it. The movement determines what complications the watch offers, how the seconds hand moves, whether it needs a battery, how long it runs between windings, and how it feels on the wrist over years of daily wear. Choosing the right movement is the most consequential specification on any watch.

This guide covers every movement used in the Watches By Cody collection in depth, without jargon left unexplained, with real watches as examples. By the end, you will know exactly what is powering any Seiko mod watch you are considering, why it was chosen, and whether it is the right movement for how you actually live and wear a watch.

First: The Foundation - What Is the Seiko NH Movement Family?

The NH series is manufactured by TMI (Time Module Inc.), a wholly owned subsidiary of Seiko that produces movements for both Seiko's own watches and the aftermarket. TMI has been making reliable automatic movements since the 1970s, and the NH series represents decades of refinement of a core architecture that prioritizes durability, serviceability, and consistent performance.

Every movement in the NH family shares the same physical footprint - the same diameter, the same dial feet positions, the same crown stem dimensions, the same case fitting specifications. This standardization is what makes the mod ecosystem possible. A case designed for the NH35 accepts the NH34, NH36, and NH72 without modification. Parts move freely between builds because the foundation is identical.

The NH35: The Workhorse

The NH35 is the most widely used movement in the Seiko mod ecosystem. It does everything a daily-wear automatic movement needs to do, reliably, affordably, and with long-term durability.

Technical Specifications

How It Works

The NH35 is a bidirectional automatic movement - the rotor winds the mainspring whether it rotates clockwise or counterclockwise, which means every movement of your wrist contributes to keeping the watch wound. Wear it for a full day and it stays wound through the night and most of the following morning without additional wrist time.

Hand-winding is available when needed. Hacking seconds - the ability to stop the seconds hand by pulling the crown - allows precise time synchronization. The seconds hand sweeps rather than ticks, moving in a continuous arc rather than jumping in discrete one-second increments. This smooth sweep has a quality that quartz ticking simply does not.

Accuracy in Practice

The rated accuracy of -20 to +40 seconds per day is the factory tolerance. In practice, most NH35 movements perform significantly better, typically running between -5 and +15 seconds per day. With proper regulation, an NH35 can realistically achieve plus or minus 5 seconds per day or better.

Watches By Cody Examples

The NH35 powers the Santos Silver White Classic, Seiko Mod Seamaster 007, Datejust Wimbledon, Royal Oak White, and Submariner Two-Tone Blue — builds where reliable daily performance matters more than a specific complication.

Common NH35 Problems and How to Fix Them

• Problem: Watch is running significantly fast — gaining 30+ seconds per day This is the most common NH35 complaint. The most likely cause is magnetisation. Modern life exposes watches to magnetic fields constantly — phone speakers, magnetic bag clasps, laptop lids, even some pillow cases have magnetic closures. A magnetised hairspring clumps together, effectively shortening its length and causing the movement to run fast.

Fix: Take the watch to any watchmaker and ask for demagnetisation. The process takes about 30 seconds with a demagnetiser and costs almost nothing. Do not attempt to demagnetise at home with magnets — you will make it worse. After demagnetisation, keep the watch away from strong magnetic sources.

• Problem: Watch stopped and won't restart If the watch has been sitting unworn for more than 41 hours, the power reserve has run out. Solution: wind the crown clockwise 20–30 turns to fully charge the mainspring, then wear the watch. It should restart immediately.

If the watch stops while being worn daily, the movement may have a more serious issue — a broken mainspring, a displaced component, or severe lack of lubrication if it hasn't been serviced in many years. Take it to a watchmaker for diagnosis.

• Problem: Running slow — losing more than 10 seconds per day consistently Consistent slow running in an NH35 that has been worn regularly usually indicates either a need for regulation or a service interval issue. If the watch is less than 5 years old and running slow, regulation is the first step — a small adjustment to the regulator lever toward + will speed it up. If the watch is 7+ years old and running slow, lubricating oils in the movement have likely degraded and a full service is needed.
• Problem: Date doesn't change at midnight — changes at the wrong time or mid-day The NH35's date should advance at midnight. If it's advancing mid-afternoon, the time was set incorrectly during setup. The NH35's date mechanism is sensitive to the position of the hands when the date wheel advances — if the time is set by rotating hands backward through midnight rather than forward, the date wheel can become misaligned. Fix: set the date correctly by advancing the time forward past midnight and confirming the date changes, then set to the correct time.
• Problem: Seconds hand not sweeping smoothly — seems to stutter or jump A stuttering seconds hand on an NH35 usually indicates low power reserve. Wind the crown 20 turns and see if the issue resolves. If the watch has been recently wound and the seconds hand still stutters, there may be a positional accuracy issue — the movement may perform differently at certain positions than others. This is normal within a range; severe stuttering across all positions suggests a service is needed.
• Problem: Hacking doesn't work — seconds hand keeps moving when crown is pulled If pulling the crown to the time-setting position doesn't stop the seconds hand, the hacking lever may have become displaced or worn. This is a watchmaker repair — the hacking mechanism needs to be inspected and adjusted. It's a minor repair but not a DIY fix.

The NH36: Everything the NH35 Is, Plus the Day

The NH36 is the NH35 with one meaningful addition: a day-of-the-week display. Same movement architecture, same performance characteristics, same reliability - with an extra complication for people who find a day display genuinely useful.

Technical Specifications

The Day Display

The NH36's day display cycles through abbreviated day names: MON, TUE, WED, THU, FRI, SAT, SUN. The day advances at midnight alongside the date. Apart from the day display, the NH36 is functionally identical to the NH35. The movement sits in any case designed for the NH35. The only difference is the dial requires two windows and the crown has an additional position for day setting.

Watches By Cody Examples

The NH36 powers the SKX007 Bronze, SKX007 Blue, and SKX007 Black Rainbow — dive-inspired builds where day-date functionality adds practical utility to a sports watch.

Common NH36 Problems and How to Fix Them

• Problem: Day display not changing — stuck on the same day The most common NH36-specific issue. The day wheel can occasionally stick, particularly if the watch has been stored unwound for a long period.

Try this: pull the crown to the day-setting position and cycle through several days manually. This usually frees the day wheel. If the day wheel refuses to advance despite manual cycling, the day wheel mechanism may need inspection by a watchmaker.

• Problem: Day display shows incorrectly — shows wrong day relative to the date The day and date on the NH36 must be set in the correct sequence. If the day and date are misaligned — for example, showing Tuesday when it's actually Thursday — the fix is to set both correctly from scratch.

Fix: Pull the crown to the quickset position and cycle the day forward until it matches today, then advance the date to match. Do not set the day by rotating the hands backward through midnight multiple times — this can misalign the day and date mechanism.

• Problem: Day changes at the wrong time — advancing mid-afternoon instead of midnight Same root cause as the NH35 date misalignment issue. The day advances in coordination with the date at midnight. If the day is changing at the wrong time, the time was likely set incorrectly.

Fix: Reset by advancing the hands forward through midnight, confirm the day and date advance together, then set to the correct time going forward.

• Problem: Day display is partially visible — only showing half a day name The day wheel sits between two positions. This usually happens when the watch stops at a moment when the day wheel is mid-advance. Wind the watch, advance the time past midnight, and the day wheel should snap fully into the next day's position. If the display remains partially visible after this, the day wheel may be misaligned and needs watchmaker attention.
• Problem: All NH35 problems apply The NH36 shares the NH35's architecture entirely. Magnetisation issues, power reserve depletion, slow running, and hacking problems all occur on the NH36 for the same reasons and have the same fixes as described in the NH35 section above.

The NH34: The GMT - A Second Time Zone

The NH34 is the GMT caliber of the NH family - the movement that makes a Seiko mod watch capable of tracking two time zones simultaneously. Introduced in 2022, it was the most significant addition to the NH movement family in years.

Technical Specifications

How the GMT Function Works

The NH34 adds a fourth hand to the standard three-hand layout - the GMT hand, typically rendered in a contrasting color. This hand completes one full rotation every 24 hours, while the standard hour hand completes two rotations in the same period.

To read a second time zone: the GMT hand points to a 24-hour scale on the bezel. Set the GMT hand to the current time in your reference time zone and the watch displays both your local time (via the standard hour hand) and your reference time zone (via the GMT hand) simultaneously.

The crown on an NH34-equipped watch has an additional position for setting the GMT hand independently of the hour hand - allowing local time to be adjusted in one-hour increments for crossing time zones without disturbing the GMT reference time.

Watches By Cody Examples

The GMT Bruce Wayne is the clearest demonstration of what the NH34 adds to a build. The black and blue ceramic 24-hour bezel pairs with the NH34's independent GMT hand to create a genuinely useful travel complication. The Batman colorway has become one of the most recognized in modern watch design, and the NH34 gives it real functional depth to match.

Common NH34 Problems and How to Fix Them

• Problem: GMT hand showing the wrong time zone — not matching the reference time This is the most common NH34 setup issue and almost always a user error rather than a movement fault. The GMT hand must be set independently using the additional crown position.

Fix: Pull the crown to the first position (GMT setting), rotate until the GMT hand points to the correct hour on the 24-hour bezel for your reference time zone, then push the crown back in. If the GMT hand is off by 12 hours, you have set it to the wrong AM/PM position on the 24-hour scale — advance it by 12 hours on the bezel.

• Problem: GMT hand jumping erratically — not advancing smoothly Erratic GMT hand movement on a well-functioning NH34 is often caused by magnetisation — the same issue that affects the NH35 but which can manifest differently in the GMT hand mechanism.

Fix: Demagnetise the watch at a watchmaker and recheck. If erratic movement continues after demagnetisation, there may be a mechanical fault in the GMT gearing that requires watchmaker inspection.

• Problem: Local time and GMT hand moving together — can't set them independently The NH34 has three crown positions: fully in (running), first pull (GMT hand setting), second pull (time setting). If the GMT hand moves with the local time hands when setting, the crown may not be pulled to the correct position. Ensure you're pulling only to the first crown position for GMT adjustment, not to the second position. If the crown positions are unclear, try pulling slowly and feeling for the two distinct detent positions.
• Problem: Watch running significantly fast — gaining 1–2 minutes per day In an NH34, dramatic timekeeping errors — particularly fast running of this magnitude — almost always indicate magnetisation. The NH34's additional GMT gearing doesn't change its vulnerability to magnetic fields. A magnetised NH34 can run several minutes fast per day. Demagnetise immediately and the timekeeping should return to normal. If fast running continues after demagnetisation, the regulation may need adjustment.
• Problem: GMT hand not moving at all — frozen while other hands work A GMT hand that doesn't advance while the hour and minute hands work normally indicates a fault specific to the GMT gearing — the additional gear train that drives the 24-hour hand has an issue.

Fix: This requires watchmaker diagnosis and is not a user-fixable problem. The GMT complication's gear train is additional to the standard movement architecture; faults in it don't affect standard timekeeping.

• Problem: Power reserve seems shorter than expected The NH34's slightly taller movement profile means it sits in the case with marginally different rotor clearance than an NH35 in some builds. If the rotor is catching on the caseback or internal case walls, it won't wind efficiently, reducing the effective power reserve. A watchmaker can inspect the rotor clearance and adjust if needed.

The NH38: Clean Dial, No Date

The NH38 is the no-date variant of the NH family - functionally identical to the NH35 except for the removal of the date complication. The result is a movement that enables cleaner dial layouts and more symmetrical designs.

Technical Specifications

Why No Date Is a Design Feature, Not a Limitation

A date window at 3 o'clock disrupts the rotational symmetry of any dial - it creates an asymmetric element that the dial designer must work around. The NH38 removes that compromise entirely. Without a date aperture, the dial surface is uninterrupted. For open-heart configurations where the movement is visible through the dial, the NH38's clean profile is not just acceptable but preferable.

Watches By Cody Examples

The Nautilus Rose Gold Open Heart uses the NH38 precisely because the open heart aperture at the center of the dial reveals the balance wheel in motion — the NH38's no-date layout keeps the surrounding dial clean and balanced, so the aperture is the undivided focal point.

Common NH38 Problems and How to Fix Them

• Problem: Balance wheel visible through open heart seems to have stopped oscillating If the balance wheel visible through the open heart aperture appears stationary, the movement has stopped. First check: has the watch been worn recently? The NH38, like the NH35, has a 41-hour power reserve. If unworn for more than 41 hours, wind 20–30 turns and the balance wheel should resume oscillating immediately.

If the watch has been worn and the balance wheel has stopped, there may be a more serious issue — a displaced component, a shock to the movement, or a severely degraded mainspring. Take it to a watchmaker.

• Problem: Balance wheel oscillating but watch still not keeping correct time A visibly oscillating balance wheel that doesn't produce accurate timekeeping usually indicates a regulation issue rather than a movement fault. The regulator lever controls how the balance wheel's motion translates to timekeeping — if it's significantly off, the balance can oscillate normally while the watch gains or loses substantial time. This is the same regulation process as the NH35; a watchmaker can adjust it.
• Problem: Open heart aperture showing scratched or damaged components In open-heart builds, the movement is visible and any damage to the dial-side components shows through.

If components visible through the aperture appear damaged — scratched bridges, a bent hand, debris — do not attempt to clean or fix this yourself. The movement needs to be disassembled and inspected by a watchmaker. Debris inside the movement that reaches the escapement can cause the watch to stop.

• Problem: All NH35 problems apply The NH38 shares the NH35's core architecture. Magnetisation, power reserve depletion, slow running, and hacking issues all occur on the NH38 for the same reasons with the same fixes. The only NH35 problems that don't apply to the NH38 are date-related — the NH38 has no date mechanism to malfunction.

The NH72: The Skeleton Movement

The NH72 is the most visually dramatic movement in the NH family - a skeletonized automatic caliber designed specifically to be seen. The bridges, the mainplate, the rotor, the gear train - all visible, all finished to be looked at.

Technical Specifications

What Skeleton Actually Means

A skeleton movement is one where the mainplate and bridges have been cut away to reveal the mechanical elements beneath. The result is a movement where you can see through from front to back - the gears, the escapement, the oscillating balance wheel, all visible in motion.

The NH72 is designed from the ground up for skeleton application - the material removal is engineered into the caliber rather than applied to an existing movement after the fact. The rotor is decorated - shaped and finished to look good from the caseback or through the dial. On most automatic movements, the rotor is a utilitarian component. On the NH72, it is a design element.

Watches By Cody Examples

The Royal Oak Midnight Skeleton uses the NH72 as the centerpiece — the skeleton dial opens the watch entirely, the movement fully visible framed by the midnight-colored surroundings and the Royal Oak's octagonal bezel. The Royal Oak RG Skeleton uses the same NH72 in a rose gold context — warmer and more refined. The SKX007 Skeleton Blue puts the NH72 inside a dive watch silhouette, an unconventional combination that works because the blue ceramic bezel provides a strong design framework the skeleton movement inhabits naturally.

Common NH72 Problems and How to Fix Them

• Problem: Skeleton movement looks dirty or has debris visible through the dial Because the NH72 is designed to be seen, any contamination inside the movement is immediately visible. Dust, lint, or debris that would be hidden beneath a closed dial on an NH35 is visible on the NH72. This is the most common NH72-specific issue.

If debris is visible: do not attempt to clean it yourself. Opening the case and attempting to blow out debris without proper tools and a clean environment typically introduces more contamination than it removes. Take the watch to a watchmaker who can properly disassemble, clean, and reassemble the movement in a controlled environment.

Prevention: avoid opening the caseback in dusty environments and minimise the time the case is open during any service or modification.

• Problem: Decorated bridges or rotor appear scratched The NH72's visible components are finished to be seen — scratches on the bridges or rotor affect the visual appeal significantly. Scratches on movement components are almost always caused by tools during assembly or modification. This is a cosmetic issue rather than a functional one; the movement will continue to perform correctly with surface scratches on the bridges.

Repairing scratched movement components requires a specialist — repolishing bridges requires removing them from the movement, polishing on an appropriate surface, and reassembling. It's possible but not inexpensive. Prevention is significantly easier than repair.

• Problem: Rotor not spinning freely — winding seems stiff If the NH72's rotor doesn't spin freely when the wrist moves, the rotor may be catching on the caseback or the rotor bearing may need attention. Because the NH72's rotor is taller and more prominently finished than standard rotors, clearance between the rotor and the caseback is particularly important.

First check: ensure the caseback is properly seated. A caseback that is not fully closed can press against the rotor. If the caseback is properly closed and the rotor is still stiff, the rotor bearing needs inspection by a watchmaker.

• Problem: Movement visible from caseback looks different from the dial side The NH72 is designed primarily for dial-side viewing. The caseback view of a skeleton movement often looks different from the dial view — you're seeing the other side of the same components, which may be finished differently or present a less decorative appearance. This is normal for skeleton movements and not a fault.
• Problem: All NH35 and NH38 problems apply The NH72 shares the NH family's core architecture. Magnetisation, power reserve depletion, slow running, and hacking issues all apply with the same causes and fixes. Because the movement is visible, the symptoms of some problems — a magnetised balance wheel oscillating irregularly, for example — may be visible to the naked eye through the skeleton dial.

The Miyota 8285: The Day-Date Specialist

The Miyota 8285 is the one non-Seiko movement in the collection - a Japanese automatic caliber manufactured by Miyota. It offers a day-and-date complication with a particularly smooth-sweeping seconds hand.

Technical Specifications

Why the Miyota 8285 Is Different

Two specifications separate the Miyota 8285 from the NH family. First, the higher beat rate: the 8285 beats at 28,800 vph - 8 beats per second - compared to the NH family's 21,600 vph. A higher beat rate produces a smoother seconds hand sweep because the hand advances in smaller increments more frequently. On a dress watch where the seconds hand's motion contributes to the overall aesthetic, this smoothness is real and appreciable.

Second, tighter accuracy: the rated accuracy of -10 to +30 seconds per day is a narrower tolerance than the NH family's range. In practice, a well-regulated Miyota 8285 can achieve plus or minus 5 seconds per day, often arriving closer to that figure without adjustment.

Watches By Cody Examples

The Day-Date Gold Roman Black and Day-Date RG Olive both use the Miyota 8285. A gold-finished or rose gold dress watch with Roman numeral markers deserves a movement that performs with the same refinement it presents — the high-beat smooth sweep and day-date display of the 8285 deliver exactly that.

Common Miyota 8285 Problems and How to Fix Them

• Problem: Seconds hand sweep seems less smooth than expected Despite the Miyota 8285's higher beat rate of 28,800 vph, new owners occasionally feel the seconds hand isn't as smooth as they expected. If the watch is new, this perception sometimes adjusts once the lubricants settle after initial wear. If the seconds hand appears genuinely to stutter or skip, the power reserve may be low — wind the crown and see if the sweep improves. A degraded mainspring or lubricants in need of service can also affect sweep quality in older movements.
• Problem: Day display not advancing — stuck on same day The Miyota 8285's day wheel can stick in the same way as the NH36's. Try manually cycling through the days using the crown in the day-setting position. If the day wheel won't advance manually, the day mechanism needs watchmaker inspection. Ensure the watch is fully wound before attempting manual day setting — a low power reserve can make the day mechanism feel stiff.
• Problem: Day and date are misaligned — showing different days The Miyota 8285's day and date must advance together at midnight. If they have become misaligned — for example, the date shows Tuesday but the day display shows Wednesday — the setting procedure needs to be followed precisely. Set the date and day together from a known reference point, advancing the time forward through midnight to confirm both advance simultaneously.
• Problem: Running significantly fast or gaining large amounts of time per day Like all automatic movements with a balance wheel, the Miyota 8285 is vulnerable to magnetisation. The 8285's higher beat rate means a magnetised hairspring can cause it to run even faster than an NH35 under the same magnetic influence. Demagnetise at a watchmaker first. If fast running continues after demagnetisation, regulation of the regulator lever is the next step.
• Problem: Seconds hand sweep looks coarser than expected for a high-beat movement At 28,800 vph, the Miyota 8285 produces a noticeably smoother sweep than 21,600 vph movements — but it is not the perfectly fluid sweep of a 36,000 vph or higher movement. Some buyers expecting a completely smooth sweep may find the 8285 still perceptibly steps, albeit much less so than a 21,600 movement. This is normal and expected behavior at this beat rate. A higher beat rate would require a more complex and expensive movement.
• Problem: Watch stopped after recently serviced or new If a new or recently serviced Miyota 8285 stops unexpectedly, check that the caseback is fully seated — a partially open caseback can interfere with the rotor and prevent winding. Also confirm the crown is fully pushed in — a crown left partially pulled prevents the movement from running in most watch architectures.

The VK63: The Hybrid Mecha-Quartz Chronograph

The VK63 is the only non-automatic movement in the collection - a hybrid mecha-quartz caliber manufactured by Seiko specifically for chronograph applications. It powers every Daytona build in the collection.

Technical Specifications

How Hybrid Mecha-Quartz Works

A hybrid mecha-quartz movement contains two distinct systems working in parallel.

The timekeeping system is quartz - a battery-driven oscillator that delivers accuracy of plus or minus 15 seconds per month regardless of temperature, position, or how much the watch is worn.

The chronograph system is mechanical - a series of levers, cams, and a column wheel that control the start, stop, and reset functions. When you press a pusher, you are engaging a mechanical mechanism rather than triggering an electronic signal. The resistance you feel is real mechanical resistance. The snap of the chronograph hand to position is a genuine mechanical action.

The result is a movement where the timekeeping feels like quartz and the chronograph feels like a mechanical watch. Neither system compromises the other.

Why This Matters for a Daytona Build

A Daytona-style watch is fundamentally a chronograph - a tool for measuring elapsed time. The VK63 delivers what matters: mechanical pusher resistance, instantaneous hand snap on start and reset, and 1/5 second chronograph precision. A fully mechanical chronograph of comparable quality costs significantly more to produce and service. The VK63's hybrid architecture delivers the experience that matters without that cost.

Battery and Maintenance

The VK63's battery lasts approximately three years. Replacement is straightforward for any watchmaker. When the battery runs low, the seconds hand begins jumping in 2-second intervals - the standard low battery indicator.

Watches By Cody Examples

Every Daytona build is powered by the VK63: Daytona Rose Gold Rainbow, Daytona Panda, Daytona Earth, Daytona Summer Racer, Daytona Panda Speed Timer, Daytona Monaco, and Daytona RG Brown. Seven builds, one movement, because the VK63 is the right movement for a chronograph application at this price point.

Common VK63 Problems and How to Fix Them

• Problem: Watch has completely stopped — no hand movement at all The most common VK63 stoppage cause is battery depletion. The VK63 runs on a battery with approximately 3 years of life. When the battery dies, the watch stops completely. Solution: replace the battery. Any watchmaker or watch service center can do this quickly and inexpensively. Use a silver oxide SR920SW or equivalent cell — confirm the correct cell type with your watchmaker.

If the battery has been recently replaced and the watch has still stopped, the battery may have been installed incorrectly (reversed polarity) or a different fault may be present. Have the watchmaker recheck the battery installation before investigating further.

• Problem: Seconds hand jumping in 2-second intervals instead of 1-second This is the VK63's built-in low battery warning — one of the most useful features of the caliber. When the battery voltage drops below a threshold, the seconds hand shifts from 1-second to 2-second jumps to signal that replacement is needed. The watch continues to keep accurate time in this mode for a period before fully stopping. Replace the battery as soon as you notice this — don't wait until the watch stops completely.
• Problem: Chronograph seconds hand not returning to zero on reset A chronograph hand that doesn't snap cleanly back to zero on reset — settling at 2 or 3 seconds instead — indicates a fault in the reset mechanism. On the VK63, this is most commonly caused by the column wheel or heart cam being displaced, which can happen after a significant shock to the watch. This is a watchmaker repair — the movement needs to be opened and the reset mechanism inspected and realigned.

Avoid pressing both chronograph pushers simultaneously, and avoid pressing the reset pusher while the chronograph is running (use start/stop first, then reset).

• Problem: Chronograph subdial hands not advancing during timing If you start the chronograph and the subdial hands (elapsed minutes, elapsed hours) don't advance while the main chronograph seconds hand runs, the subdial mechanism has a fault. The VK63's subdials are driven by a separate mechanism from the main chronograph hand — they can fail independently. This requires watchmaker diagnosis and is not a DIY repair.
• Problem: Pushers feel loose or have no resistance when pressed The VK63's mechanical pusher feel — real resistance when you press the chronograph buttons — is one of its defining qualities. If the pushers feel loose, springy, or offer no resistance, the pusher seals or the internal lever mechanism may have an issue. First check: ensure the pushers themselves are properly seated in the case. If the pusher tubes are loose or the gaskets have degraded, the pusher feel can change significantly. A watchmaker can reseal the pushers and restore the correct tactile response.
• Problem: Timekeeping is accurate but chronograph is slightly off — starts a second late or early A very small delay between pressing the start pusher and the chronograph hand moving is within normal tolerance for a mechanical chronograph mechanism — even on the VK63. If the delay is more than a fraction of a second, the chronograph clutch mechanism may need cleaning or adjustment. Dirt or dried lubricant in the clutch can slow its engagement.
• Problem: Main time hands running correctly but at wrong speed — hours hand completing rotation in wrong time This is a very unusual fault that almost always indicates a battery issue — specifically, a battery with incorrect voltage. Different battery types produce different voltages; a battery that is not the correct specification for the VK63 may cause the timekeeping motor to run at the wrong speed. Replace with the correct battery type and confirm with a watchmaker.
• Problem: All chronograph function lost after significant shock The VK63's mechanical chronograph mechanism is more vulnerable to shock than the quartz timekeeping system. A significant impact — dropping the watch on a hard surface, a sharp blow to the case — can displace the column wheel or other lever components in the chronograph mechanism. The timekeeping typically continues working because the quartz oscillator is more robust. The chronograph requires watchmaker repair to restore.

The Complete Movement Comparison

Which Movement Should You Choose?

• Choose the NH35 if you want the most proven, most versatile automatic for daily wear. The default choice for a reason.
• Choose the NH36 if you want to know the day of the week at a glance alongside the date. Functionally identical to the NH35 with that one meaningful addition.
• Choose the NH34 if you travel or work across time zones. The GMT complication is one of the most genuinely useful in watchmaking.
• Choose the NH38 if you want a clean, no-date dial - particularly for open-heart designs where dial symmetry matters. The removal of the date window is a design decision, not a limitation.
• Choose the NH72 if you want to see your movement. The skeleton architecture transforms the dial into a window into mechanical craft.
• Choose the Miyota 8285 if you want a day-date complication with a higher beat rate and smoother seconds hand - particularly for dress watch applications.
• Choose the VK63 if you want a chronograph. The hybrid architecture delivers mechanical pusher feel and quartz accuracy in the same caliber.

Movement Care and Maintenance

For Automatic Movements

Wear the watch regularly - automatic movements stay healthier with consistent use. Service every 5-7 years as lubricating oils degrade over time. A professional service cleans, re-oils, regulates, and pressure tests the movement. Any reputable watchmaker can service an NH-series or Miyota movement worldwide.

Avoid strong magnetic fields. Magnetisation can cause dramatic timekeeping errors. A watchmaker can demagnetise a movement quickly and inexpensively. If your watch begins running minutes fast or slow without warning, magnetisation is the likely cause.

Regulate when needed. If your automatic movement runs consistently fast or slow within the normal range, regulation brings it to within plus or minus 5 seconds per day without a full service.

For the VK63 Hybrid

Replace the battery every 3 years or when the seconds hand begins jumping in 2-second intervals. No other regular maintenance is required for the quartz timekeeping component.

Choosing the right watch is ultimately about more than just specifications—it’s about finding a piece that fits seamlessly into your daily life. The best watches are the ones you don’t have to think twice about—reliable, versatile, and naturally aligned with your personal style.

At Watches By Cody, our goal is simple: to offer watches that combine timeless design, dependable performance, and real-world wearability—without the unnecessary markup often found in traditional luxury retail. We focus on pieces that look refined, feel right on the wrist, and hold up over time.

If you’re ready to find a watch that fits both your style and your lifestyle, explore our latest collection at Watches By Cody and discover the piece that works for you.