This mark is quite rare and it does not appear in any of Walt Pich's field guides.  The unique maker's mark is 'Hinode Sakura' which means 'Sunrise in a Cherry Blossom'.  It's been commonly referred to as the Sunrise float.

This green float measures 4 1/4 inches in diameter.

From my limited research, there appears to be only 3 of these floats known to exist in collections; with this recently found float (pictured) being the third one.  Of course, no one knows how many more of these floats may be tucked away in storage or hidden in attics over the past few decades. 

I've read that these floats may have been produced in the 1920's.  If that's the case, then I think it may be less likely that many more of these floats will be found in Japan.  This assumes that the same analogy that applies to Kanji rollers holds true for the Sunrise floats.  This logic goes that over time these floats get used up at their source and the beachcombed floats are the ones that are most likely to have survived.  Again, this is just an hypothesis.  If you have evidence either way I'd love to hear it (just write and post a review below).

This float surfaced in Ocala, Florida in 2017.