the MiG-15 and MiG-15UTI in China

Deino once again with a silly or maybe even stupid question … this time regarding on old type (in fact not my personal darling !), the MiG-15 and MiG-15UTI in China.

Fact is that that in early 1950, with China entering the war in Korea on the horizon, MANY MiG-15 were delivered via the SU to the PLAAF.

Said is that in line with the build-up of a modern aircraft industry under the guidance of Soviet experts, the SU sent 847 MiG-15 engineers and specialists to China to begin construction of the fighters by October of 1951.
However no MiG-15 or MiG-15bis was ever manufactured in China since this agreement was changed to the MiG-17 (aka J-5).

– The still mysterious question therefore remains – in my opinion it is only some kind of Western invention or misinformation which over the years became FACT – why is the MiG-15/MiG-15bis called J-2 ??

– And then, since the Chinese aircraft industry / Shenyang built the MiG-15UTI trainer versions … is this really called JJ-2 ?? Again there are many contradicting reports on that !

– Besides that … are there any information available about the numbers of MiG-15 delivered and esp. the number of each version ??

Thanks in advance,
Deino