Seiko Presage SARW001, SARW003, SARW004, SARW005, SARW007, SARW009, SARW011, SARW013, SARW025 (aka SPB041J1), SARW027, SARW029 (There may be many more, please leave them in the comments below)
Seiko claims an accuracy rating of +25 – 15 seconds per day in normal temperature conditions.
The caliber 6R27 is similar to the 6R20, 6R24, and 6R21,and even shares the same instruction manual.
What are the differences?
All 4 variations have the power reserve indicator at 9:00 and a date subdial at 6:00. The difference is that the 6R20 and 6R21 have a day of the week subdial at 3:00. The 6R24 has a retrograde day of the week indicator at 3:00 (as well as a retrograde date indicator at 6:00. Which also explains why the 6R24 has 31 jewels instead of 29). The 6R27 shown here only has the power reserve indicator and date subdial.
To say that the 6R15 is Seiko’s answer to the Swiss workhorse that is the ETA 2824 would be an understatement. Bottom line is that the 6R15 caliber is that GOOD a movement and with the sheer number of ETA-powered watches out there, it is sometimes nice to have something different to stir up the masses.
It is not as refined as their Grand Seiko movements of course, but certainly can hold up to some of its Swiss competitors, especially in the same price range.
For official instruction manual for this movement, see this pdf
Here is a press-release from 2016 that mentions the 6R27 in the Presage line.
The movement shown above is from a Seiko Presage SARW027. It is only available in Japan. this timepiece was tribute to the First Automatic timepiece from Seiko since 1956. So this model has 1956 limited watches.
Other models that celebrate 60th Anniversary of the Seiko’s first Automatic are SRQ019J1 (aka SARK001 in JDM), SRQ021J1 (aka SARK003 in JDM) and SSA309J1 – all of which are from the Presage line.