The Famous Calibre 101 Movement by Jaeger-LeCoultre. The calibre 101 was introduced in 1929 and at the time was celebrated as the smallest watch movement ever made measuring 14 x 4.8 x 3.4 mm. The Duoplan movement itself was the idea of Paris watchmaker Henri Rodanet an ingenious wheel train layout that allowed the movement to retain its timekeeping properties yet could be made in very small sizes for lady’s watches.