Please help with this saucer is the marks CHINESE or JAPANESE???

[Lumhechati]

I have this saucer the marks match up to Chinese but someone told me the marks where Japanese is this correct the pieces have turned greenish brown????Please help

[Lumhechati]

Having trouble uploading

[Stan]

This is a 4 character Qianlong mark, I have not seen this mark on antique Japanese porcelain before so Im thinking it could be a fake the mark is off center and the foot rim is not a traditional period foot, a 20th century copy I think of Chinese Imari.