Transposition table utilizattion

[hgm]

Ah, I see. It is indeed very important that new positions will always be stored in the hash table. So always-replace is viable, having only depth-preferred is not. But having depth-preferred next to an always-replace scheme (such as you get with 'shallowest-of-N' replacement) is highly superior to a pure always-replace scheme. For highly overloaded hash tables, there is further benefit from reserving an equal fraction of the table for all drafts.