Disclaimer: I am not an expert and often need help identifying items myself.
This does not look to be an authentic Chenghua period piece. From my observations of Chenghua porcelain, the blue dye is is a grayish/smoky dark blue. This blue dye looks similar to the blue dye used in Japanese Imari like you mentioned. Also, it appears as if the inside of the bowl is transfer printed, which would not be the case for something made during the Chenghua period. Keep in mind, if this piece were authentic then it is around 600 years old, which is highly unlikely. The mark's brush strokes don't appear Chinese and do look Japanese. If you examine Imari pieces, you'll see brush stroke similarities. The Japanese often mimicked the Chinese styles and marks because Chinese porcelain was more revered than Japanese. I doubt it's a "fake", but rather a spurious mark that appears Japanese to me. But then again, there are two other users on here who know way more than I do. I would wait to hear what they say if they take a look. Even if it's not what you expected, it's still a nice piece. Good luck!
