1954 Asahiflex IIb. This is the 3rd release of the Asahiflex.
1st - Asahiflex I
2nd - asahiflex Ia
3rd - Asahiflex IIb
4th - Asahiflex IIa
The original Asahiflex (Asahiflex I) was the first Japanese 35mm camera, which was based on a 1939 German design. A second release was produced, the Asahiflex IA, with some minor modifications for flash use.
Like most Asahi cameras, there were slight adjustments made during the production cycle. The original IIB has an arrow to point to the shutter speed, whereas later models (like this one shown) use a triangle. After the IIA was released, a round plug will be shown on the front of the camera, presumably so that Asahi could make a single camera housing for both models.
The Asahiflex IIB (Shown here) introduced a unique feature of automatically bringing the mirror down to it's original position using an "Instant Return Mirror". This innovation was a coup for Asahi, as both rangefinder and other 35mm designs required manual intervention to return the mirror to the original position, which caused a condition known as "Mirror Blackout"