Instead, hundreds of watches with numerous different designs, intended for different uses, have carried the emblematic shield logo with the 5 in the center.In fact, the watches have been signed several different ways — Seiko 5, Seiko 5 Sports, Seiko Sportsmatic 5, Seiko 5 Actus — with movements ranging from 17 to 25 jewels.The movement has 17 jewels and is completely automatic with a half rotor taking up most of the visible surface and a non-hacking day/date movement. Because this is a mass-market movement, Seiko focused on durability and not on aesthetics.This movement is so plain as to be boring, but up close, if you dare open the case, it’s quite striking.Yet another was overall water resistance — although in those days the words “water proof” were used (a labeling that would have the Federal Trade commission scrambling their lawyers if it occurred today). Tradition (and many an online watch forum entry) says it’s for the following five key attributes of all Seiko 5 watches: (Some sources combine Diaflex and Diashock while separating Day and Date.) However, Seiko’s website commemorating the 50th Anniversary states a slightly different, somewhat more general set of attributes: It’s interesting that Seiko doesn’t specifically state the Diaflex and Diashock systems — or overall movement durability — in their list.In any case, this third attribute was less a technological innovation and more an innovative design criteria for the Seiko 5 sub-brand. Perhaps this is because the two movements, while significant, were not unique to the Seiko 5.
These movements – and watches – come in multiple forms and flavors with different complications and cases.Now that the disassembly is actually starting to reveal the innards of the movement, I’ll try to understand how it works.Now that the we’ve finally exposed the heart of the time display unit, it is probably a good time to try to understand how the various parts are driven.To do that, I counted the teeth of each of the wheels this side of the movement. The cannon pinion carries the minute hand so we know it makes a full revolution every hour, or 24 revolutions per day.It rotates at the same speed as the centre wheel, to which it is connected via friction coupling.