I would like to use the font Japan for commercial use but I can not find any licensing information for the font. The downloads only include the font itself.

Note of the author on the dafont-download-page:
Traced form an old Dover Book on handwritten type. This font is free for non-commercial use and donationware for commercial use. Make a donation through PayPal my account there is: turoturom@yahoo.es
I have contact the mailadress but no answer. It doesn't say how much to donate for commercial use?!
How much is recommend to donate?

Goto http://marioarturo.herobo.com/ and click contact.