The Seiko/TMI/SII caliber NH35 (NH35A) is a hand-windable, hacking upgrade from the Seiko caliber NH25A (read: NH25A vs NH35A). The earliest documentation on this movement that we were able to find was issued on 2/14/2011, this also corresponds with the 2011-2012 time frame that the first NH35A powered watches started hitting the market.


The NH35A is currently one of the world’s most popular automatic movements and is widely available in many affordable/microbrand watches.