7,8 & 9 Limited Tablebases

[Derek]

Hi,

Are there any incomplete but useful 7,8,9 tablebases that feature common pawnless endings?

eg KRRBKRRB but not KRRPKRRB

I understand that if a 8 man tablebase included a pawn it would promote to too wide a dataset to analyse upon promotion?..yes?... but I wondered, & am wondering what scope one could partially extend the present 6/7 man limitations in specific and useful areas, where the pieces cannot promote.

Thanks,
Derek.

[h.g.muller]

Pawnless endings in general require the entire EGTB to be made, as all moves within the TB are reversible.

It is far easier to make incomplete EGTBs for pawny endings, as pawn moves are irreversible, and to make a partial TB with a white pawn on e5 you don't need any positions with the pawn on e2, e3, e4 or any other file. It is true you would have to worry about promotions, though.