>>43985938>learn japanese first,which is easierHaving learned both in college, I will say that Japanese is harder due to the grammar alone. Neither are particularly hard once you get the hang of it, but the only truly difficult aspect of Chinese is writing. Pronunciation of Chinese is not as difficult as people claim if you are good at mimicking sounds. Japanese is difficult in the aspects of reading, writing, and grammar. Most Chinese words are bi-syllabic, so even if your pronunciation is slightly incorrect, you can still be understood for the most part.
And I hate to disappoint you, but learning one is not a shortcut to learning the other. They don't really have anything in common except for the borrowed Chinese characters that are used more or less as abbreviations/hieroglyphics for some Japanese words. The pronunciations, meanings, and even appearance of those Chinese characters aren't always one-to-one when they are used in Japanese.