The Speedmaster Triple Date, often called MK40, is fitted with caliber 1151 (or ETA/Valjoux 7750) and measuring just 39mm is considered a crowd pleasing size. It is however not a (manual) Reduced model but an automatic. This caliber watch fits in between the larger and the smaller models and was produced only for the Japanese market since 1996, with a fairly limited run into the early 2000s, so they are both uncommon and collectable. In fact, all Speedmasters Date of the 3520 series are by now over 20 years out of production.
The caliber 1151 used here is designed and constructed to be pure chronograph, and is therefore a fully dedicated movement, whereas a caliber like the 3220 consists of a time-only movement with an add-on movement for the chronograph functions - the Dubois-Dépraz 2020 chronograph module.
The colorful or quircky models (like this one certainly is) were usually released in the Asian market. So what happens if you add on day, date and month? Next to the tritium lumed hands and markers you get a triple date racing model that’s using an extra hand in the form of a fighter jet to point out the date. This pointer date is set via the crown pulled out to first position and it can only be set forwards. The month is then progressed by advancing the date past the 31st. Logically sound, but this comes with an issue. Should you go past your desired date you are left with three options. The first is to simply ignore having the wrong date. Not my cup of tea. The second is to accept defeat, and put on a different watch until the 3520 has run out of juice, allowing you to catch up with the wrong date. Acceptable, but not ideal. The third option is to correct the date by advancing it… by a full year because, remember, the month goes right long too.
Notwithstanding all it lovable quircks this is a limited production model Speedmaster that is the total opposite of the moonwatch but with the ultimate workhorse movement. Added bonus is that the tritium (only applied to the first series of the MK40) will gracefully and will add a nice "real" patina to the hands and minute markers. No faux colors here...
With the current Master Co-Axial 3861 caliber, which takes the Speedy Pro further into luxury territory than ever, the 3520s present a cool and truly vintage tool watch alternative..