If it makes you feel any better, toga thinks your line is mate in 12 :-) (which is the problem I've talked about in other threads, the material winning alternative filter for mates doesn't kick in when the alternatives are also mates).
Richard.
Yes, I kept thinking about this problem all week in the back of my mind. A day or two later I realized that it ends up being a forced mate, with the king walking over to finish things. Obviously, I didn't work out very much detail when I originally did the problem, I simply saw that I had a substantial advantage and also overlooked the mate in 2. Live and learn I guess.