Here are a few pictures of the gorgeous in-house movement Citizen cal 8110A that my friend Sergio was kind enough to let me use on the site so all of us could enjoy! Thank you Sergio!

The movement here is the Citizen automatic, 23 jewels, calibre 8110A with hand winding capability. It was produced by Citizen starting from 1972. It is a vertical clutch chronograph (beating at 28.800 bph) with column wheel and fly back function. (how many modern chronograph do that, and what is their cost?) Lets don’t forget it has a day and date indicator. The fly back function means that you can reset the chronograph while in motion and it will start again without needing to go the entire process of pressing stop-reset-start. So, one push can do all of this. Of course that if you want to stop it you can go the classic stop-reset way. A particularity for this movement is that when you want to change the day you should pull the crown to second position (for changing the date) and push and release the reset (1 o’clock) button. It is 27 mm wide and 6.9mm high. The column wheel/vertical clutch design of the movement advices to leave the chronograph running for most of the time (this way you can also see the beautiful sweeping central second hand in movement), but from time to time it should be stopped. This is a chronograph that needs to be used. It is not made for design purpose but for timing.

Citizen 8110A

Features
automatic chronograph, 60s, 30min, 12h, pillar wheel
flyback feature: reset and immediate restart
day: set by reset-pusher in crown position for date setting, 2 languages
date: quickset

Data
12”’, Dm= 27.0mm
H= 6.9mm
23 jewels
f = 28800 A/h
power reserve 40h

Stem Citizen 065-178

Remarks
1970-
ball-bearing rotor
usually as bull head (crown/puschers at 12h, day/date at 6h)

Example, year: signature; shock device
1977: Citizen Japan, 23 J.; Parashock

Data about this movement from here.

Read more about one of my favorite Citizen, one powered by this awesome movement here: https://vintagecitizenwatches.com/2013/12/24/citizen-bullhead-chronograph-67-9356/