Conservative Relevance Zone Search in Connect6

This paper proposes a new search mechanism called Conservative Relevance Zone Search (CRZS), and it surveys numerous candidate moves to prove or disprove a sudden-death position. CRZS is inspired by Conservative Threat Space Search (CTSS), so it performs conservative defense on single-threat position to prove or disprove it. The experimental results show that the new search mechanism is significantly more efficient than Relevance Zone Search (RZS) on positions for which TSS solutions are available in Connect6, and it can solve 100% of the tested puzzles.