The Patek Ellipse ref3738 (or the Quartz-variant ref3838) stands out in the numerous vintage Ellipse-models: not only by size but especially in a technical way, as being the only one with a so-called monocoque case. A case without a removable caseback. And as usual with such outliers, immediately the question appears: Why. Why is it technically so different from what was used before for decades and even there after -- just from the late 1990s this case-design seems to prevail and every Ellipse is made like that. If we take a look at the so-called Patek-authority John Reardon (collectability: *klikk), then we get lost in micro-differences between the Ellipses: dial-color, movement-iterations... everything counts but not the Elephant in room: it's the case.

My suggestion: Is it possible the case of the 1978-presented Patek Philippe Jumbo-Ellipse ref3738, ie. the now classic and most sought-after PP-Ellipse is technically a copy of the Seiko U.T.D.-GoldFeather Calatrava ref6810-0020 from 1973 (ooh!)? The time-distance is a serious hint: 3 to 8 years is the development-cycle for a new model at Patek. But there is more...

• an Ellipse in the size of the ref3738 has exactly the diameter of 34mm when transformed to a circle -- the size of the Seiko ref6810-0020;
• Patek has never before made a monocoque-case... seems like they were impressed by the Seiko and with a reason, in my opinion;
• the four years between 1976 - 1980 were basically Pateks Monocoque-years: beginning with the Gerald Genta-designed Patek Jumbo-Nautilus ref3700 and ending with the also Genta-designed ref3770 Ellipse-Nautilus in 1980 -- the latter being a nautilized Ellipse ref3738; in between, in 1978: the Jumbo Ellipse, the only Ellipse with a monocoque-case; yes, all earlier and later Ellipse came with a three-part case with usual caseback; the ref3738 was probably not Genta-designed but: given the fact that Genta was (obviously) intensively working with Patek during this era and Genta was working intensively with Seiko during this era as well, allows the assumption that he not only knew the Seiko ref6810-0020 but also inspired Patek to do something similar;

If this is not the case, then the question remains: Why is the most relevant Ellipse ref3738 such an outlier in the Patek-portfolio and what has lead to this? If someone has other hints -- supportive or opposing this assumption: please let me know.