On Mon, 22 Jul 2013 13:16:51 -0700, Joe Riel wrote:
Has anyone modified a Japanese saw to improve the grip?

You might consider a high friction tape.
http://www.leevalley.com/en/wood/pag...at=1,130,43332
http://www.leevalley.com/en/wood/pag...10,43466,32184