Grand Seiko SBGW301: specifications and what to check

Thirty seconds at the crown

Almost every reference documented here winds itself; the handful that do not are chronographs. This one is neither: the 9S64 is specified as manual-winding, with no rotor at all, in a plain three-hand watch.

That makes it the most diagnostically generous watch here, because winding a mainspring by hand puts your fingers directly on the condition of the barrel and the train.

Start from stopped. Turn the crown steadily and pay attention to three things.

Consistency. Resistance should be even, turn after turn. A patch that goes suddenly light or suddenly heavy is a finding.

Build. It should get progressively firmer as the spring winds, then arrive at a clean, definite stop.

Count. Roughly how many turns it takes should be similar each time you do it. A barrel that reaches full wind noticeably early on the second attempt is telling you something.

On an automatic, all of this is hidden behind a slipping bridle and a rotor you cannot feel. Here it is right under your hand, free, in half a minute.

Do not force it, and tell the buyer the same

The corollary matters as much as the test.

An automatic movement's mainspring is designed to slip at the end of its travel, so an owner cannot overwind it. A manual movement's is not. When this crown stops, it has stopped, and continuing to turn is how mainsprings break.

Plenty of buyers have only ever owned automatics. Say this to them explicitly at handover, in writing if the watch is shipping. It costs a sentence and prevents a warranty conversation.

A display back with nothing in the way

The case back is specified as see-through, secured with six screws — and because there is no rotor, the view is unobstructed.

Use it. Wind the watch while looking through the back and you can see the train turn. Screws, bridges and jewels are all visible under a loupe, and so is any evidence of a rough previous service: burred screw slots, scratched bridge surfaces, fingerprints.

Six screws also means six chances for someone to have chewed a head. Check them.

Polish, proportions and the strap

Grand Seiko describes the lugs as Zaratsu polished, with an intricate slope that widens toward the tip and a distortion-free mirror surface.

That is precisely what a careless refinish destroys. Hold the case so a straight edge — a window frame works — reflects along the flank, and follow the reflection. It should stay straight. Ripple, softness at the lug edges, or a lug that has lost its taper means material has been removed, and on this reference the finishing is much of what the buyer is paying for.

The dial is off-white and domed, rising gently at the centre, with diamond-cut peak-shaped indexes and hands individually bent by hand to follow the curve. Look at it from an angle, not just straight on, and check the hands sit close to the dial across their whole sweep.

Sizes to quote: 37.3 mm diameter, 11.7 mm thick, 44.3 mm lug to lug, 19 mm lug width, 61 grams. The strap is crocodile leather, the water resistance is splash resistant, and both of those facts belong in the description together.