I finally got null moves to work in Vicki. I had some trouble with the capturing of the king (which caused Vicki to hang), but I eventually got it fixed. I am utterly amazed at the effect of null moves in the engine. With null moves Vicki searches (on average) 1-2 plies deeper and even more later in the game. In late-middle games, depths of 12 plies are reached! That is without any other form of pruning or transposition tables. The new version of Vicki is already playing on FICS and I am conducting tests against the older version to evaluate the improvement.
Why didn't I have this ready for the WRCC?