Seiko Mod / Custom Build featuring NH35A movement with aftermarket 'Great Wave' Seigaiha Rotor
Customized Tool/Sport Watch (Automatic) · Custom/Independent Build using components from Seiko Instruments Inc. (TMI) and various aftermarket parts suppliers.
Period: Modern Custom (2020s-present); Neo-Vintage aesthetic influenced by Japanese 'Great Wave' art and heritage Seiko dive watch design.
Type
Customized Tool/Sport Watch (Automatic)
Brand
Custom/Independent Build using components from Seiko Instruments Inc. (TMI) and various aftermarket parts suppliers.
Movement
Automatic, Seiko TMI Caliper NH35A (21,600 bph / 3Hz, ~41-hour power reserve, 24 jewels, hacking and hand-winding).
Dimensions
Diameter: 40-42mm, Thickness: 13-14mm, Lug-to-Lug: 46-48mm, Lug Width: 20-22mm.
Description
This is a custom-built mechanical watch showcasing the incredibly popular 'Seiko Mod' culture. The centerpiece is the NH35A movement, a workhorse beloved for its reliability, which has been upgraded with a laser-etched Seigaiha (traditional Japanese wave) rotor. This specific modification pays homage to the 'Great Wave off Kanagawa' and Seiko’s maritime heritage, combining robust Japanese engineering with artistic personalization.
Key Features
Customized Seigaiha wave-pattern rotor; workhorse NH35 movement; exhibition caseback; bespoke assembly rather than factory production.
Dial Description
Not fully visible, but likely a 'Seiko' branded or sterile aftermarket dial often paired with this specific wave-patterned rotor.
Case Material
Brushed and polished 316L Stainless Steel; often utilizes aftermarket 'SKX007 style' cases.
Crystal Type
Likely Flat or Domed Sapphire with potential AR coating; standard for NH35 custom builds.
Bezel Details
Unidirectional rotating bezel (not fully visible), likely featuring a ceramic or aluminum dive-time insert.
Crown & Pushers
Screw-down crown, likely situated at the 3 o'clock or 3.8 o'clock position; no pushers visible.
Bracelet or Strap
Likely a Stainless Steel Oyster or Jubilee-style bracelet with a folding deployment clasp.
Caseback Details
Exhibition/Display screw-down caseback, allowing a clear view of the NH35 movement and the custom Seigaiha wave rotor.
Movement Type
Automatic, Seiko TMI Caliper NH35A (21,600 bph / 3Hz, ~41-hour power reserve, 24 jewels, hacking and hand-winding).
Water Resistance
Typically 100m to 200m (10-20 ATM) depending on the case seals and the skill of the assembler; requires pressure testing to confirm.
Origin & Provenance
Movement made in Malaysia or Japan (Seiko/TMI); components sourced globally; assembled by an independent hobbyist or professional modder.
Age Estimate
Circa 2021-2024; based on the high popularity of the laser-etched wave rotor aftermarket part in recent years.
Cultural Significance
Represents the 'Modder' movement within horology, where enthusiasts take factory watches or parts to create unique, one-of-a-kind timepieces, often bypassing traditional luxury gatekeeping.
Condition Notes
Very Good/Excellent. The movement plates appear clean. The rotor shows sharp, well-defined laser etching. No visible signs of moisture or lubricant oxidation.
Value Estimate
$250 - $450 USD. Value is driven by the quality of the individual case, dial, and crystal used in the build rather than brand name alone.
Care & Maintenance
Service movement every 5-7 years. Although NH35 is robust, check water resistance annually if used for swimming. Avoid strong magnets and extreme shocks.
Similar Watches
Seiko 5 Sports SRPD series, Seiko Prospex 'Turtle' or 'Samurai', or various microbrands like Islander or San Martin.
Interesting Facts
The NH35 is the unbranded version of Seiko’s 4R35 movement. It is the most popular movement in the world for 'microbrands' and independent 'modders' due to its affordability and durability.