Sorry Clint
Terrible mistake from me in the first place.
The M-2 marking has nothing to do with Japan at all. I should have looked in the Putnam book straight away and not
just rambled from memory, which is fading too quickly I'm afraid.
The M-2 is a British B condition marking issued to Short 10 Oct 1930.
All available photos to me of the KF-1 (S.15) model wearing these markings were taken in England.
One source states it used the M-2 markings also after arrival to Japan, but I have no verification of that.
I have only seen one other photo of a H3K1 built by Kawanishi and that is also in the Putnam book.
It has the Tateyama Katakana symbol and what looks like :2. Listed as the third one built in Japan.
So Clint, just one aircraft (no rubbish like M-1, just forget that) and yes the M-2 is the one built in Britain.
Looks like I better spend the winter in hibernation....
Cheers
Stig