The Seiko Presage Craftsmanship Series Porter Classic Collaboration SPB449 is result of a collaboration with Japanese fashion label Porter Classic. It’s modelled on the Laurel, the 1913 Seiko timepiece that was the first wristwatch made in Japan, giving the SPB449 a look typical of early-20th century timepieces that were essentially pocket watches converted into wristwatches.

Porter Classic was founded by a member of the family that founded Porter Yoshida, the cult luggage brand known for its functional and pricey nylon bags. The brand offers clothing and accessories with a vintage feel, including jackets that accommodate pocket watches. Its take on the Presage is a modest tweak on the original: a black enamel dial made by the workshop of Mitsuru Yokosawa, the longtime supplier of enamel dials for the Presage.

Initial thoughts

Collaborations between watch brands and lifestyle labels are now common, so the SPB449 isn’t a surprise, especially since it’s between two uniquely Japanese brands. Still, Seiko rarely does collaborations with the Presage Craftsmanship series. The aesthetic, however, is not new as this similar to earlier Presage limited editions, namely the SPB359 of 2022 and last year’s SPB441, that were similarly inspired by the Laurel.

While the difference between this and the earlier Laurel edition is basically a change of dial colour, the SPB449 stands out thanks to the high-contrast, black enamel dial. It’s striking even though the case is undersized at 35 mm in diameter (the vintage Laurel was even smaller).

Priced at US$2,300, the SPB449 offers good value. The fired enamel dial is uncommon in this price range, and this is unique with its Laurel-inspired case that is distinct from the conventional Presage.

Fired enamel

Inspired by the wristwatches of the early 20th century that were often pendant watches modified for the wrist, the case of the SPB449 features an oversized, onion-shaped crown and “wire” lugs. The case is polished steel that’s finished with a “super hard coating”, a proprietary Seiko treatment has increases the surface hardness of the case alloy.

Fitted with a box-shaped sapphire crystal, the case measures just 35 mm in diameter and 12.3 mm high, dimensions that evoke the vintage Laurel. This is one of the smallest Presage models in the Seiko catalogue.

The black enamel dial sports spade hands and Breguet numerals, just like the original Laurel. The register at six indicates the current hours on a 24-hour scale; it is not a second time zone.

Powering the SPB449 is the cal. 6R5H, an automatic movement that offers three days of power reserve and beats at 21,600 beats per hour (3 Hz).

The solid back is engraved with a silhouette of Katsuyuki Yoshida, founder of Porter Classic, along with the limited-edition number

Like earlier Laurel-inspired models, the SPB449 is delivered with a “pull-through” strap that resembles a NATO-syle strap. In fact, it’s packaged with a pair, one in black and another in brown.

The SPB449 is presented in a box unique to the edition inspired by jūbako, the tiered boxes traditionally used to present food in Japanese cuisine.

Key facts and price

Seiko Presage Craftsmanship Series Porter Classic Collaboration Limited Edition
Ref. SPB449

Case diameter: 35 mm
Case height: 12.3 mm
Material: Stainless steel
Crystal: Sapphire
Water resistance: 50 m

Movement: Cal. 6R5H
Functions: Hours, minutes and 24-hour indicator
Winding: Automatic
Frequency: 21,600 beats per hour (3 Hz)
Power reserve: 72 hours

Strap: Black cordovan pull-through strap and an additional brown strap

Limited edition: 500 pieces
Availability: Now at Seiko boutiques and retailers
Price: US$2,300

For more, visit seikowatches.com

The vertical clutch has become the de facto standard in modern chronograph movements thanks to its mechanical and practical benefits. The widespread and varied use of the vertical clutch is illustrated by the many recent movements that employ the mechanism, ranging from the Rolex Cosmograph Daytona to the Breitling B01 to the MB&F LM Sequential Evo.

The proliferation of the vertical clutch is easily explained by its merits. Having explained the construction of a vertical clutch, we now turn to its advantages over the traditional horizontal clutch (or lateral coupling).

Figure 1: A simplified cross section of a vertical clutch

A vertical clutch serves to transfer energy from the going train of the movement to the chronograph going train, accomplishing this via a vertical motion. Figure 1 illustrates its key parts: a flywheel (yellow) geared to (or even part of) the going train; a cone (grey) that is linked to the chronograph seconds mobile, and vertically tensioned by a spring (red); a pair of pincers (blue) that engage with the cone, lifting or lowering the cone. 

When the cone is raised and engaged with flywheel, the chronograph starts running, and when the cone drops and disengages, the chronograph stops.

One of the most apparent advantage of the vertical clutch is the low kinetic friction generated during coupling and uncoupling of the chronograph, as friction is produced only by the sliding motion of the pincers and the vertical motion of the cone.

The Rolex Cosmograph Daytona that employs a vertical clutch

Another advantage is the instant engagement of the chronograph train with the going train. Because flywheel and cone are co-axial, and the cone is already under tension, the two essentially snap together when the pincers release. As a result, the motion transfer relies on a static moment of friction, which results in little or no wear to the moving parts.

This instant engagement also means the absence of “stutter” – a jump or wobble in the chronograph seconds hand – when the chronograph is engaged, which is an occasional issue with laterally-coupled chronographs. As the cone and flywheel come together, the energy transfer from the flywheel to the cone is instant, so the chronograph seconds hand starts moving in a crisp and accurate motion, with no forwards or backwards jumps at the start of engagement, improving the precision of the elapsed time measurement.

The Rolex cal. 4131 of the Daytona

And finally, an oft-forgotten advantage of the vertical clutch is its ability to relay torque more reliably to the chronograph’s minute and hour registers. Because the vertical clutch engagement is strong and secure, it enables the chronograph seconds mobile to drive all the other chronograph registers.

Horizontal clutch chronographs, on the other hand, often have the hours register separately powered by the rotation of the barrel in order to alleviate some of the stress on the engaged clutch and gear train. This is the case for the cal. 3861 and its preceding cal. 1861 inside the Omega Speedmaster Moonwatch.

One of the newest chronograph movements on the market, the Breguet cal. 728 inside the Type XX also employs a vertical clutch

And cons

All things considered, there are also a few disadvantages associated with a vertical clutch. The clutch assembly is oftentimes a single unit made up of components soldered or stamped together, preventing disassembly, which in turn means the vertical clutch assembly cannot be repaired or serviced, and instead has to be replaced as a unit. The lack of serviceability may be reflected in increased service costs since the entire clutch assembly needs to be replaced, instead of just a faulty part.

However, some brands opt for serviceability, like Rolex does with the cal. 4131 in the Daytona, which employs a vertical clutch that can be conveniently dismantled during service, allowing its constituent components to be replaced where necessary.

The vertical clutch in the Rolex cal. 4130/4131 that can be dismantled during service

Another potential drawback is linked to certain executions of the vertical clutch. Imprecise tolerances in the parts of a vertical clutch, or a clutch that is inadequately lubricated, can result in slight malfunctioning that generates friction when the chronograph is disengaged because of excess play or contact between the chronograph axle and flywheel.

In such cases, the movement can become more accurate when the chronograph is engaged, since this eliminates the friction generated between the axle and flywheel. MB&F mitigates this possibility with a fully-jewelled vertical clutch, namely synthetic ruby rings set in the axle. (We already explored the interesting architecture of the LM Sequential EVO in-depth here.)

The fully jewelled vertical clutch in the MB&F LM Sequential EVO

The MB&F LM Sequential EVO

Less significant but perhaps more relevant for the wearer are the aesthetic disadvantages of the vertical clutch. The mechanism can increase movement thickness due to its vertical orientation, as opposed to the lateral orientation of the horizontal coupling.

Despite its technical disadvantages, the classical lateral coupling presents visuals that are impossible with a vertical clutch

Another is simply the movement visible through a display back: a vertical clutch is practically invisible due to its construction, while a lateral clutch brings with it an intricate network of levers and springs.