Platinum wristwatch with standard time, chronograph, rotating date disc, and power reserve.

The unique platinum Montblanc Star Nicolas Rieussec Monopusher Chronograph Open Date, which Montblanc has presented to Only Watch is based on the spirit of Rieussec's original chronograph, with two rotating skeleton discs.

In making the watch mechanism an open secret, the two counter discs, the date disc and parts of the dial have extensive cut-out areas through which you have a direct view of the individual wheels and the movement's main plate (decorated with Geneva stripes). Also visible – among other things – is the chronograph mechanism's vertical disc clutch, which lies centrally between the three rotating discs for the seconds, minutes and date.

"Made entirely at the Montblanc manufactory at La Locle," says Montblanc's technical and development manager, Yannick Renaudet, "you read this watch by its hands that are fixed – it is the dials that turn and so completely change the way of reading the time, and there is a complexity connected with the discs and the linkage of the discs."

The Montblanc manufacture caliber MBR110 is a hand-wound movement with an excentred time display, a rotating date disc and a chronograph with classical column wheel control featuring an innovative vertical disc clutch. It is operated using a monopusher in the side of the case at 8 o'clock, which is very practical because it ensures that the button is not pushed unintentionally and can be operated with the thumb of the right hand.

Standard time is shown on an off-center calibrated ring with Arabic numerals. This frames a cut-out in the dial in which the skeleton date disc rotates. The current date is shown by a fixed red triangle at 12 o'clock, which points to the date disc. Another very practical feature is quick adjustment of the hour and date when traveling through different time zones.

This can be carried out regardless of the position of the minute hand in either a clockwise or anticlockwise direction. The movement has two barrels, which generate a 72 - hour power reserve. The remaining power reserve is shown on a display at the back of the movement, which can be seen through the sapphire glass cover.

The case, made of platinum with a special finishing and is crowned by a convex sapphire glass with antireflective coating on both sides, while a screw-in, see-through, sapphire glass back provides a view of the aesthetically designed and decorated movement, together with the power reserve display. The watch is manually wound using the solid, knurled crown, which is decorated with an inlaid Montblanc emblem.