Seiko · Prospex Sea and Presage Sharp Edged Series

Seiko SPB317J1 vs Seiko SPB331J1

9 published specifications differ between these two, and 5 are identical. Every figure below is what the manufacturer states for that reference; nothing is inferred from the other watch.

What differs

Specification	Seiko Prospex Diver 200m, 6R35, silicone bandSPB317J1	Seiko Sharp Edged Series Kabuki-inspired Limited Edition, 6R35SPB331J1
Case	Stainless steel, 41.0 mm	Stainless steel with hard coating, 39.3 mm
Diameter	41 mm	39.3 mm
Thickness	12.3 mm	11.1 mm
Lug to lug	46.9 mm	47.2 mm
Water resistance	200m / 660ft diver's	10 bar
Crystal	Curved sapphire crystal, anti-reflective coating on inner surface	Sapphire crystal, anti-reflective coating on inner surface
Case back	Screw case back	See-through and screw case back, engraved LIMITED EDITION and serial number
Bracelet	Silicone band, 20 mm between the lugs	Bracelet length 195.0 mm, 20 mm between the lugs
Movement notes	Precision stated as +25 to −15 seconds per day. Stop second hand and date display. Magnetic resistance 4,800 A/m. LumiBrite on hands, indexes and bezel. Total weight 100.0 g.	Precision stated as +25 to −15 seconds per day. Stop second hand function and date display. Total weight 83.0 g. Limited edition of 2,000 pieces.

What is identical

Worth knowing as much as the differences: these are the specifications you cannot use to tell the two apart.

Lug width: 20 mm
Calibre: 6R35
Movement: Automatic with manual winding
Power reserve: Approximately 70 hours
Jewels: 24

Stated for one, not the other

These rows cannot be compared, because one maker publishes the figure and the other does not. An empty cell is a gap in the manufacturer's documentation, not a gap in the watch — and not a licence to fill it in from the other column.

Bezel	Unidirectional rotating bezel	not stated
Crown	Screw-down crown	not stated
Clasp	not stated	Three-fold clasp with push button release

What the differences cost you

Each note below follows from the published figures in the tables above — what they mean for intake, for a listing, and for the handover. Nothing here estimates a price or a margin.

Do not describe these the same way

200 metres on the SPB317J1 against 100 on the SPB331J1. Both are more than daily life asks for, so the number is a listing-accuracy question rather than a practical one: quote each watch its own figure, and remember that neither rating survives an unserviced case by itself.

What to check on each

SPB317J1

Bend the silicone band fully back on itself at both lug ends and look into the crease. Silicone fails from inside a fold, and a flat inspection will miss cracking that is about to become a failure.
Confirm the calibre is the 6R35 rather than the 6R55 used elsewhere in this family. Both are 24-jewel automatics from the same maker, and they carry different reserves.
Weigh it against the published 100 grams. That is remarkably light for a steel 200-metre diver and is largely the band rather than the case, which matters if a buyer intends to fit a bracelet.

SPB331J1

Photograph the engraved serial number on the case back and record it. On a numbered edition the serial is part of the object, and a buyer will ask for it before agreeing a price.
Examine the hard coating at the lug edges and around the clasp for wear through to the steel beneath. A coated case cannot be polished back, so any breakthrough is permanent and must be disclosed.
Confirm the crystal is the flat sapphire published for this reference rather than the curved sapphire used on the Prospex models, since the two are not interchangeable parts.

Sources

Not affiliated with Seiko. Specifications are read from each manufacturer's own published documentation on the dates shown and may change; the manufacturer's current documentation governs.