Hello again. Japan issued several variations of this clock. Some have brass cases, others are aluminum. They use a Seikosha pocket watch movement. These movements have the usual winding the setting mechanisms with added modifications for use in aircraft.

A common problem with these clocks is found in the extra gearing and other parts which permit the clock to be wound and set by a knob sticking out from the front of the case, below 6 o'clock (and on other models above 12 o'clock). When the winding and setting mechanism is out of order it's usually not an easy repair. The gearing can get ground-up and may even require making replacement gears.

Collectors should be careful to avoid these clocks when out of order. Another issue to avoid is buying one of these clocks if it has been improperly repaired.

On a popular auction site I have seen a couple of Japanese aircraft clocks which are missing the winding/setting knob. There is a hole where it should be sticking out but it's otherwise missing. Instead of repairing or restoring the original mechanism, someone removed it entirely. In place, I can see a conventional winding and setting crown sticking out from the side of the case. This appears to have involved cutting a hole through the side of the setting mechanism cover. A real hack-job!

An all important lesson; if you are going to collect something be sure to study what a good original example is supposed to look like. Avoid the junky stuff, unless you are looking for parts or entertainment.

Here is a close up of a proper winding mechanism.

Great example Greg. These always tend to be overshadowed by Luftwaffe examples. Fantastic the winding mechanism is still intact. Great shape also! It’s a keeper!!

Thanks, Greg. This is a great post and excellent advice, especially for collectors who do not really understand what it can take to put an aircraft clock back to rights. Too many sellers either do not know themselves or in some cases may prey on an eager collector's unwarranted enthusiasm with statements like "it is just overwound and will be an easy fix" and similar drivel.