Interesting enough, the strength increase is still disappointing given the major rewrite. Therefore, I am now performing experiments with tournaments and test positions to find more opportunities to enhance its strength.
I like this test position (white to move wins), which I found on TalkChess, one of my favorite forums on chess (thanks to Chess Imager for generating the diagram).
This is an anti "null move" position. The old BikJump, which tries a null move after full move generation only when sufficient moves are possible, found the forced mate very quickly. The new BikJump performs the null move prior to full move generation to enhance searching speed. As a result, however, the mate is no longer found in reasonable time (just like many strong chess engines fail to find it quickly). Common wisdom is that the second approach is better, since the position above is unlikely to occur in real games. It leaves me somewhat weary though. Would a strong human chess player find the mate quickly? And if so, do current chess engines, which beat the strongest players but struggle on positions like this, truly pass the Turing test? Opinions?