. . . my understanding is that G O's solution is proprietary. I saw an article a few years back in Watchtime that outlined the differences between the various solutions offered by different manufacturers . . . Omega's implementation seems similar, but I don't know enough about it to say for certain that it's identical to Glashütte's. Omega is my other favorite manufacturer, but large dates are few and far between in their line-up; recently, they've moved towards the expanded aperture solution in some of their models that exhibits the leading and trailing dates as well as the current date, which I'm not particularly fond of . . . cordially, Art