Simple Watch. Simple?

Even the simplest mechanical wrist watch is comprised of a surprising number of parts, and none of the part are superfluous. I think it would be interesting to have a look on the inventory of the parts in a simple, but high-graded wrist watch.

The AP calibre 2120 is a 28 millimeter round, and 2.45 millimeter thick automatic winding movement with hours and minutes display. It utilizes 36 jewels, and runs at 19,800 beats per hour.

The parts comprising the watch are (1) the winding rotor; (2) rotor retention clip; (3) rotor bearing; (4) rotor bearing retention ring; (5) rotor support ring; (6, 7, 8, 9) rotor rim screws; (10) 21K rotor rim; (11) mainspring barrel bridge; (12) barrel bushing; (13) ball-bearing winding transfer gear outer race; (14) ball-bearing winding transfer gear inner race; (15) retention screw; (16) ball bearings (O.K. there are six!); (17) switching rocker upper jewel; (18) barrel click upper jewel; (19) reduction wheel upper jewel; (20) hand wind-disconnect wheel upper jewel... ...

In fact, the whole calibre consists of 169 parts in total.
Simple Watch. Simple? For full illustration, please take a look at the original article by Walt Odets