[BigJJ]

The value of the ball is in the great provenance.

I would write a letter detailing your grandfather and the restaurant by name and specific location, how famous people came to eat there, and how this signed ball was your grandfather's, etc. and sign before a notary. I would do this not just for selling purposes, but also for the future should you leave to future generations who might want record or wish to sell. It is the uniqueness of this ball, which was signed all the way in Japan, that is special. Air travel was not as speedy in that day! There are collectors who are interested in international tours, who may be particularly interested in the piece. and Japanese Yankee collectors in Japan.

Post playing days DiMaggio balls sell for about 200-250. Surprisingly single signed balls, from when DiMaggio was a player - in very good condition - go only for about 500-1000. This ball is faded.

But because of the special provenance, and I would definitely add a menu or business card from the restaurant to accompany your letter, I would say the value is about 2k.

If you wish to sell the piece, there is a store in Manhattan called Gotta Have It, and I recall that they may have collectors for such a piece.