It is OK to use a chess engine while attempting to solve this study! In fact, the most enjoyable and tricky experience comes (in my opinion) if you use a program with the Nalimov 5-man tablebases installed (having 6-man ones on disk may make this too easy, though you yourself are humanly welcome to consult the Knowledge4IT Free EGT Server for individual positions) on moderately slow hardware such as was common in 2001---getting say 300k--500k nodes per second. At 1,500k nodes per second on processors 2Ghz and above, some of the key tricky parts do get resolved more quickly than would make the best challenge.

Solution with full analysis.