Definitely Soviet as well as the Manual of Marxism-Leninism: Second Edition by Otto Wille Kuusinen

My honest opinion:

The Shanghai textbook is honestly garbage compared to the Soviet one, imho.

It's too "ideological" in its prose and keeps swiping at imagined enemies, tbh, which honestly kinda speaks to the growing dumbassery of the cultural revolution (a period in which nothing - and you can all argue with me on this, but that's what my Chinese comrades say - nothing was achieved, either in the short-term or ultimately). I've watched the Yukong documentary and a few pro-cultrev documentaries, but they're just fucking garbage, in my eyes, because they really whitewash the fuck-up that was that time-period and the "Great Leap Forward."

Do not get me wrong: things were achieved, such as women's equality, the banning of foot-binding and slavery, etc., that had nothing to do with the cult-rev or Great Leap Forward.

The Soviet Union after 1956 was flawed, but frankly? China and Deng's revolutionary reforms were needed; nothing was being accomplished except nukes and... useless pig-iron.

That said... The Sino-Soviet split was stupid and China helped many nations in Africa (so did the Soviet Union, but that's a discussion for a different time).

Also, USSR was needlessly antagonistic, though so was the PRC.

Okay, but seriously, I've seen excerpts of the Shanghai textbook and I know people that have read it, and what I've read doesn't inspire confidence.

IMHO.