Described as a 1940 Koch scooter prototype with a CZ 98 engine.

This picture came from the Jawa-CZ Owners Club archive of literature.  The only thing I know about it is that the picture was described as a 1940 Koch Scooter prototype with a CZ 98 engine.
J.F.Koch was the chief designer at the Praga factory.  When Praga ceased production of motorcycles in 1934, Koch set up his own factory and produced a limited number of a very advanced 348 cc unit-design ohc single.  Koch ceased manufacture in 1935 which makes the suggested date for this scooter of 1940, a bit of a puzzle.
This scooter particularly caught my interest because of the description of being powered by a CZ 98 engine, since I have recently bought a 1935 CZ 98 (pictures of this autocycle are elsewhere in this section). I would guess that this uses the same Bezrychlostní (single speed) engine as my 98.  There was a later 98 cc CZ  with a three speed hand change but it’s hard to see how a hand gear change could be mounted on the machine shown.