Montblanc Calibre MB R100
In an attempt to be taken seriously as a manufacture, Montblanc worked with other Richemont units, especially including ValFleurier to develop their own in-house chronograph movement. This work resulted in the 2007 introduction of calibres MB R100 (hand-wound) and MB R200 (automatic). Both are double-barrel mono-pusher chronograph movements with date function, though Cal. MB R100 has a power reserve indicator on the reverse while Cal. MB R200 has a 12-hour second time zone complication with day/night indicator instead.
The dial arrangement of both calibres is unusual The time display is shifted towards 12 00, making room for chronograph minute and hour discs at roughly 4 30 and 7 30. There are no running seconds. Displaying the chronograph time on a disc is reminiscent of the early chronographs created by Nicolas Rieussec, for whom Montblanc named the series of watches containing these calibres. Cal. MB R100 includes a central date hand or disc. A later variant includes day and date apertures at 9 00 and 3 00, similar to the day/night and rising date apertures on Cal. MB R200.
The top plate of the movement is nearly solid, stretching from 8 00 to 4 00. It is decorated with Geneva waves and includes the text, “Montblanc/Le Locle/Twin Barrels”. A thick bridge rests just beneath this with an individual movement number and “Cal. MB R100” engraved on it. Beneath this bridge, the symmetrical going train wheels are visible along with the vertical coupling for the mono pusher chronograph. At 6 00, the Gyromax balance is clearly visible. An aperture in the top plate allows the column wheel to be viewed. Another aperture at 12 00 includes a power reserve indicator hand and a view of the gears below.
Although the calibre in all automatic Nicolas Rieussec watches is marked MB R100, many variations have appeared. All feature the same basic functions with very little difference in movement architecture.