The two buttons at 4:30 and 7:30 adjust the central hour hand back or forward in 1-hour increments. The date is linked to the central hour hand and can also move backwards or forwards. The time indicated at 3 is the "home" time and it has a day and night indication.
Pretty useful when traveling to different timezones.
Gorgeous watches on display today! I now have developed Speedy Deficiency Syndrome…and the cure may never be obtained. (I strapped on a damn Apple today, so I’m not showing pics. Gotta go with what you got, I guess 😀 )