If there is one watch manufacture that consistently makes a virtue of being lean, it must be Piaget. The brand has many records in this area, including those for thinnest automatic minute repeater and overall thinnest automatic wristwatch, with thinnest movements in both instances. Earlier in this story, we covered the leanest gem-set mechanical movement, and now we turn to a watch that was shown before the SIHH, the thinnest of them all at an unbelievable 3.65mm thick.

This particular Altiplano uses a different approach than anything Piaget has ever made because the manual-winding calibre and the case are one and the same. Basically, the base plate is the case back, thus removing another level of thickness and adding exponentially to the complexity of making the watch. To our knowledge, the Altiplano 38mm 900P is unlike any other mechanical watch currently in production. The 38mm watch is currently offered in 18K white gold (S$39,700) and 18K pink gold; there are also two gem-set versions, both in 18K white gold, with one version featuring a fully-set case and dial.