Using Jacobi constraints. Either bK moved or bRa8 moved. In the latter case, what unit is on a8? By counting, there is no promoted bP. So either bRa8 pendled, or (unlikely) bRh8 reached a8 while bRa8 is on g3. These are the three cases to be checked. The first case gives the solution together with a pair of tries which fail after B6; the other two offer no solutions or tries.
condition Circe stipulation dia 8.0 forsyth rsbqkbB1/ppp1ppp1/8/7p/8/5Sr1/PP1PPPPP/RSBQK2R
Using Jacobi constraints. Either bK moved or bRa8 moved. In the latter case, what unit is on a8? By counting, there is no promoted bP. So either bRa8 pendled, or (unlikely) bRh8 reached a8 while bRa8 is on g3. These are the three cases to be checked. The first case gives the solution together with a pair of tries which fail after B6; the other two offer no solutions or tries.
condition Circe stipulation dia 8.0 forsyth rsbqkbB1/ppp1ppp1/8/7p/8/5Sr1/PP1PPPPP/RSBQK2R
