FLYBOYJ
"THE GREAT GAZOO"
Sorry a bit sensitive on my part.
They were not copies rather a Japanese version they could produce. Lower RPM due to lack of high strength steels the Germans initially used, lower compression on each in the compressor section, no on board starter engine.
"The Ne-20 was made possible by Imperial Japanese Navy engineer Eichi Iwaya obtaining photographs and a single cut-away drawing of the German BMW 003 engine."
Ishikawajima Ne-20 - Wikipedia, the free encyclopedia