For all old school mechanics; this watch face uses a Vernier scale to show the time
https://en.wikipedia.org/wiki/Vernier_scale

The external dial is placed with 11/12th of the normal spacing. The center tickmarks are placed the normal way. The last hour the zero on the outer dial has passed is the number of hours. The line that most closely lines up with one of the hour ticks indicates the number of minutes.