A 54-move masterpiece...


In the puzzle, 1. ... Qh6+ is a faster mate.
a) 2. Kg8 Rg1+ 3. Kf7 Qe6+ 4. Kf8 Rg8#
b) 2. Ke7(e8) Qe6+
i) 3. Kf8 Rg1 and 4. ... Rg8# next
ii) 3. Kd8 Rd1 and take on d2 next.
c) 2. Kf7 Qe6+
i) 3. Kf8 Rg1 and 4. ... Rg8# next
ii) 3. Kg7 Rg1+ 4. Kh7 Qg6+ 5. Kh8 Qg7#