Ref:1554 Production of this reference began in 1942. To the best of our knowledge only three examples of this reference were produced, all in pink gold, the present example being the only example with a luminous ?Military Type dial?. The large size of the watch is atypical of the period and places it alongside the references 530, 570, 1506 and 1579. All of these references were made in comparatively small numbers to the chronograph wristwatches under 35 mm in diameter. The only other comparable wristwatch with chronograph available at the time this watch was made was the reference 1506 of which only three pieces are known, two are pink with pink dials and one in yellow gold with silvered dial. Antiquorum sold a pink gold example of reference 1506 on the 24th of October 2005 in Geneva as lot 116. The two watches are excellent examples of the creativity and diversity of design of the Patek Philippe firm during this period. The majority of the watches with avant-garde case designs were produced in very limited numbers to test market response, with the present watch appearing to be one of the rarest watches ever made by Patek Philippe.