If Japan wants bases early, there are only 3 places. 3 more emerge (HK, FIC, MALAYA) that are much better positioned but these produce first units J4 if you J2, not J2 regardless.
If you don’t have at least 1 land factory, and especially if you J1 and pull troops off the mainland, China can easily go out of control. A few games ago, I bought 1 J1 and another one on J2 or J3 and China still blasted me.
The Manchurian one is valid from game start because you’re going to need to economize, you can’t really churn out 3 tanks x 2-3 factories for many turns and still bulk your fleet. So, the Manchuria factory is building things like infantry and artillery, not tanks, and in G40, you will need these small units on offense or defense if the USSR stuck around.