Seiko · Prospex Samurai · Ref SRPL13
Cut, not cast.
The Samurai is the Seiko diver with flat planes where the others have curves. The SRPL13 is the current 41.7mm version: 200m rated, 4R35 automatic inside, black dial and bezel, on a bracelet with a diver’s extension.
Water resistance
200m
https://www.seikowatches.com/us-en/products/prospex/srpl13
Case
41.7mm · 12.3mm
49.5mm lug to lug, 20mm lugs, per Seiko
Movement
4R35
Seiko in-house automatic, hacking and hand-winding
Power reserve
41 hours
23 jewels, 21,600 vph
Crystal
Hardlex
https://www.seikowatches.com/us-en/products/prospex/srpl13
The armour case
The Samurai nickname is about the case. Instead of the rounded cushion shape on most Seiko divers, the mid-case and lugs are cut into flat facets that meet at edges. Brushed tops, polished bevels, and a crown guard at four o’clock shaped to match.
The line dates to a 2004 original and came back into Prospex in 2017. The SRPL13 is the current black-on-black version. Seiko lists it at 41.7mm across, 12.3mm thick and 49.5mm lug to lug, which is smaller than the older Samurai references and smaller than our catalogue once recorded.
200m, properly
This is a Prospex, so the 200m rating is a diver’s rating rather than a lifestyle figure. Screw-down crown, unidirectional bezel with a lumed pip, LumiBrite on the hands and all twelve markers, and a three-fold clasp with a diver’s extension for a wetsuit.
The crystal is Hardlex, Seiko’s hardened mineral glass. Sapphire arrives further up the Prospex range, not here.
The 4R35
Seiko’s 4R35 is the date-only version of the automatic in the 5 Sports line. It runs at 21,600 vibrations per hour on 23 jewels with a stated 41-hour reserve, and it hacks and hand-winds. The date sits between four and five o’clock, colour-matched to the dial.
There is no day window on this reference. Seiko’s page lists date and a stop-seconds function, and the photograph agrees.
Specs
- Reference
- SRPL13
- Case size
- 41.7mm
- Case material
- Stainless Steel
- Movement
- Automatic Caliber 4R35
- Caliber type
- Seiko In-House Automatic
- Crystal
- Hardlex Crystal
- Water resistance
- 200m (20 ATM)
- Power reserve
- 41 Hours
- Complications
- Date
- Jewels
- 23 Jewels
- Frequency
- 21,600 vph (3 Hz)
- Origin
- Made in Japan
Specifications as published by Seiko. We research from manufacturer documentation and published sources rather than hands-on testing. Researched 2026-09-03.
Verdict
A 200m Prospex diver with a case shape nothing else at the price shares, now sized at 41.7mm.
Strengths
- Genuinely distinctive faceted case, brushed with polished bevels
- 200m diver’s rating with screw-down crown and diver’s extension
- In-house 4R35, hacking and hand-winding
- LumiBrite on every marker and hand
Trade-offs
- Hardlex, not sapphire
- 49.5mm lug to lug is long for a 41.7mm watch
- Date only; no day window
- 41-hour reserve
Buy it if
A diver or a desk diver who wants a Seiko 200m watch that does not look like every other Seiko 200m watch.
Skip it if
You prefer a rounded case, want sapphire, or need a day display alongside the date.
FAQ
The nickname comes from the case. Its sharply angled, faceted planes look like armour plating, unlike the rounded cushion cases on most Seiko divers. Seiko itself uses the name.
Sources
Researched and last updated 2026-09-03. We do not test watches in hand; every figure above is traceable to the manufacturer or the sources listed here.
Seiko Prospex Samurai SRPL13
Reference SRPL13 · $500–$1,000
Prices and availability change; the band above is a research figure, so check the current listing.
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