Fritz Khula Piano was made by some manufacturers all over the world.
F.Khula made in Hamamatsu, Japan by TOYO Piano MFG. (Apollo Piano) 's serial numbers (printed on golden frame) are in the link.
Fritz Khula Piano were also made by:
Lester Piano (Hamamatsu, Japan);before 1965
Sakamoto Piano(Hamamatsu, Japan);before1965
(after 1966, F.Khula was made by TOYO in Japan)
Maridos piano Co.(Phillippins)
N.Y. Euterpe Piano
Fritz Khula (West Germany)you can see serials after lift up top roof,then engraved right side of wooden body.
If your own F.Khula was made by TOYO, #83543 will be 1976 model.