Seiko · Seiko 4R72 skeleton

Seiko Presage Style60's Skeleton and Cocktail Time Star Bar power reserve: inside the 4R72

The Seiko Presage Style60's Skeleton (SSA461) and the Cocktail Time Star Bar limited editions (SSA455, SSA457) run on Seiko's skeletonised 4R72. From a full wind it runs about 41 hours, or 1.7 days.

Updated September 2026 · Based on manufacturer specs, published reviews and watchmaker/owner reports

Watches that use the Seiko 4R72

The 4R72 is Seiko's gold-toned skeleton version of its 4R automatic. Its plates and bridges are cut away so the movement can be seen through an open-worked dial. It's used in a small number of Presage models, which is why it's far less familiar than the 4R35. If your Presage shows the gear train through the front of the dial, has a gold-coloured movement and has no date, it's almost certainly a 4R72.

Specs at a glance

History and where it came from

The 4R72 belongs to the same 4R family as the 4R35 and 4R38, and Seiko covers all of them in one instruction manual. It shares their 3 Hz beat, 24 jewels and 41-hour reserve. What's different is how it looks. Seiko cut away much of the plates and bridges, finished the movement in gold tone and opened up the rotor, so that a skeleton dial has something worth showing. Reference sites describe the silver-toned 4R71 as the same movement in a different colour.

It became widely known in 2022 with the Presage Cocktail Time Star Bar limited editions, made with the Tokyo bar whose drinks inspired the Cocktail Time series. On those watches the dial has ten arc-shaped cutouts spreading out from the balance at 9 o'clock, meant to look like ripples on a freshly poured cocktail. Monochrome called the movement "an entry-level movement, but also a reliable workhorse". The Style60's Skeleton SSA461 followed, with the left side of the dial cut away and the vintage-style indexes kept.

Accuracy in the real world

Seiko rates the 4R72 at +45 to -35 seconds a day on the wrist, the same as every 4R in its manual. Skeletonising changes how the plates look, not the balance, hairspring or escapement, so there's no reason to expect it to keep time differently from a 4R35 or 4R38.

Owners of 4R movements commonly see a few to 20 seconds a day fast, with some near zero and a few close to the edge of the spec. As with any Seiko at this level, it isn't adjusted in multiple positions at the factory, so the rate shifts with how the watch sits overnight and how fully it's wound. A watchmaker can regulate it with the conventional regulator arm.

Reliability and servicing

The working parts are standard 4R parts, with Seiko's Diashock shock protection, so there's no reason to expect it to be less durable than a Seiko 5. There's no known failure specific to the skeleton version.

Servicing is where the skeleton matters. A skeletonised, gold-toned movement shows every mark, so a service needs more care than on a hidden 4R35. A standard NH35 can't replace it without spoiling the look. You'd need another 4R72 or, for a watch that isn't Seiko-branded, a skeleton NH movement. Seiko service centres can handle it.

Quirks worth knowing

• No date. With nothing to set but the time, a stopped 4R72 is quick to restart, and there's no late-night date danger zone.
• AM and PM don't matter. With no date or 24-hour hand, the watch doesn't know whether it's morning or night.
• Winding from stopped. The crown only winds clockwise. A stopped 4R72 won't start straight away because the spring has little torque at first. Keep winding until the seconds hand moves.
• Legibility. Skeleton dials trade readability for show. On the SSA461 and Star Bar the hands sit over busy movement parts, so check you can read it at a glance.
• You can see it run down. The balance is visible from the front, so you can tell at a glance whether it has stopped.

How it compares

• Seiko 4R38: an open heart rather than a full skeleton. You see the balance through a single cutout, and it's used in the Cocktail Time Open Heart.
• Seiko 4R39: the open heart plus a 24-hour hand, in the open-heart Style60's and the Japanese Garden series.
• Seiko 4R35 / 4R36: the same movement hidden behind a solid dial, with a date or day-date.
• Seiko 6R5J: Seiko's upmarket open-heart calibre, with a 72-hour reserve. It costs more but survives a weekend off the wrist.

Living with the 41-hour reserve

Skeleton watches tend to be occasion watches, and 41 hours doesn't go far. Wear your Style60's Skeleton to dinner on Saturday, take it off at midnight, and a fully wound 4R72 stops around 5pm on Monday. If it only got a few hours of wear, it may be stopped by Sunday. A Star Bar limited edition that lives in its box will need winding almost every time you pick it up.

At least you can see the problem coming. Glance at the balance, and if it's still, wind it a few dozen turns by the crown before you set the time. To plan ahead instead, Watch Winder counts down the 41-hour reserve for each watch you own and reminds you before it stops. For a particular weekend, try the "Will my watch stop?" calculator.

Verdict

The 4R72 puts a basic, dependable Seiko automatic on show, and that's all it is. For the price of a Presage, the SSA461 and the Star Bar editions let you watch the gear train work through the dial, with hacking, hand-winding and 4R reliability underneath. You still get the 4R's loose official tolerance and a reserve that won't cover a weekend, and the finishing is plain up close. Buy it for the view, wind it before you wear it, and it will serve you well.

FAQ

How long does the Seiko Presage Style60's Skeleton run off the wrist?

The 4R72 in the SSA461 runs about 41 hours from a full wind, roughly a day and three quarters. If it was only lightly worn, it will stop sooner.

Does the Seiko Cocktail Time Star Bar hack and hand-wind?

Yes. The 4R72 in the SSA455 and SSA457 stops the seconds hand when you pull the crown out to set the time, and it winds by turning the crown clockwise.

How accurate is the Seiko Presage SSA461?

Seiko rates the 4R72 at +45 to -35 seconds a day on the wrist. Most 4R movements run well inside that, and a watchmaker can regulate one closer.

Why did my Seiko Star Bar SSA457 stop in its box?

The 4R72 only stores about 41 hours of power, so a watch left in its box stops within two days. Wind it a few dozen turns by the crown before wearing it.

What is the difference between the Seiko 4R71 and 4R72?

The finish. Reference sites list the 4R71 as silver-toned and the 4R72 as gold-toned, with the same size, jewels, accuracy and 41-hour reserve.

Does the Seiko 4R72 have a date?

No. It shows hours, minutes and seconds only, which keeps the skeletonised movement clear to see.

Is the 4R72 a real in-house skeleton movement?

Yes. It's made by Seiko, with the plates and bridges cut away and finished in gold tone, not just a cut-out dial over a standard movement.

Sources

• Monochrome: Seiko Presage Cocktail Time Star Bar SSA455J1 and SSA457J1 hands-on
• Seiko: Presage Style60's SSA461J1 product page
• Seiko: Presage Style60's collection page
• Seiko: Instruction manual for 4R35/4R36/4R37/4R38/4R39/4R71/4R72 (PDF)

Keeping it running

• On an average day an automatic gains roughly 4 hours of reserve per hour on the wrist, so about 10 hours of wear fills the Seiko 4R72 skeleton. Desk days charge more slowly.
• Most automatics can also be wound by the crown. If yours has stopped, a few dozen turns gets it going before you put it on.
• Off the wrist it stops about 41 hours after it was last full. Stopped sooner?
• On a watch winder, start at about 650 turns per day, both directions. Winder settings for every movement.
• If it does stop, don't set the date between 9pm and 3am. Check if it's safe.

All Seiko movements

Never let it stop

Watch Winder counts down the reserve of every watch you own and reminds you before one stops. It already knows the Seiko 4R72 skeleton: type your watch's name and the reserve fills itself in.

Manufacturer's published figure. Real reserve varies with the watch's age and service; check your manual.