Chess Online

I give it five, for sure. I finally got it, after making one slip-up toward the end. Hard to believe anyone gave it less than five. Show me a harder one! This was a little harder than a similar mate-in-19 we had a while back, with the same motif of bishop maneuvering to bring about a small change (in this case, gradually playing c2-c3-c4 to guard d5), followed by a further maneuver to position for mate. Brilliant conception! I'm pretty sure I saw this somewhere, but so long ago that all I remembered was the gradual pawn push. Forgot the double piece sacrifice, followed by mate by pawn.

Of course not... but there were several elements contained in those 22 moves, which increases the difficulty factor. A good indication of a problem's difficulty is the percentage of people solving it... which is only 2% right now!

For the purpose of this problem, yes! In terms of what you would call "real" chess, probably not. Are you new to the problem world? Totally different than regular chess. I didn't use to like problems too much, was mainly interested in improving my OTB game. But as mental exercises, problems (i.e., mate in 2 or more, or even helpmates and others) are excellent.