pawnchain f5-e6-d5, piece sac f5.cql

cql()

flipcolor {
    {result 1-0}
    line --> {
        wtm {movenumber < 21} { power A <= power a + 1 }
        pf5 pe6 pd5 Pe5
    } --> [QRBN]f5 --> pf5 --> [KQRBN]f5
}