A hand winder today, the ‘Seven’ – and an interesting model, since it is the manual winding version of Citizen’s second generation Jet automatic. The movement is designated 4000, compared to the automatic calibres named 41xx, with their circular gear rotors. The case is a monocoque design (indicated by an encircled ‘x’ on the back) and mine is from April 1966. The date change on this, as with the auto calibres as well of course, is different from the norm – crown in running position winds the watch, one pull out and you can change the time. Then the crown is pulled further out and back in again to change the date  – got to be careful when adjusting the time, since pulling it too far changes the date. Citizen called this their ‘Easy Change’ mechanism. The day window is nice, showing a wheel with both English and Kanji printing:

More info on this and other variants can be found here: https://sweep-hand.org/2011/06/29/this-weeks-featured-watch-9-the-seven/