Rebel wrote:hyatt wrote:When did Frans Morsch supposedly give us recursive null-move? It was certainly in Cray Blitz in 1989 as the version on Carey's "computer chess history" web site will show. The first reference I am aware of is "Selective search without tears" by Don Beal which laid this out nicely.
This gets interesting. You never claimed this until now. You only have said (and multiple times BTW) you and Bruce have tossed with the idea of "null-move" but eventually could not find an improvement and dropped the idea. That is no surprise because the strength of null-move comes from its recursive use. And that was new. The inventor: Frans Morsch. Frans talked to Donninger who wrote an article in the ICCA journal (1994/95). Then in 1996 the topic exploded in RGCC, recursive-null-move was heavily discussed and finally implemented in every chess program. Talking commercials.
I assume you made a typo claiming recursive-null-move as your own, you probably meant null-move.
Ed
As "my own?" I thought I made it quite Clear that my implementation came after Don Beal published "Selective search without tears." My very first implementation allowed just one null move. We went to recursive at some point, but I had thought it was around 1992 until we found the 1989 version of the Cray Blitz source that Carey has on his web site. When I looked at the code, I thought "I don't remember doing this" but when I looked at the change-log that was carried along with the source code, there it was. It was most definitely R=1 and not 2 or adaptive at that point in time. But it was certainly there, and it also was certainly not my idea.
Burt Wendroff sent me a copy of Beal's paper, and I had null-move in and working in Cray Blitz an hour later. I just checked to confirm the date and this was 1986 and not 1989. So I was actually off by 3 years as to when we first used null-move. And beal used it before that.
So, apparently, the time-line (since I don't have anything but some paper logs of CB output, and then this one source version with a changelog that ended around the end of 1989 was found and sent to me along with the now public version of the source that does run on a PC) was:
1986. null-move, R=1, one null-move in any path.
somewhere between 1986 and 1989, null-move R=1, only restriction was two consecutive null-moves were not allowed.
And then somewhere in 1995-1996 I worked with varying R from 2 to 1, after discussions on R.G.C.C with John Stanback (he was playing with this as well).
About 1.5 years ago I went to pure R=2 everywhere.
And I don't claim originality in any of the above. Don "opened pandora's box".