
Solution
1.+P2b

if 2.Rx2b, 3.Rx3c+. if 2.Bx2b, Rx3b+

1.+P2b

if 2.Rx2b, 3.Rx3c+. if 2.Bx2b, Rx3b+

1.P*6d

if 2.Sx6d, 3.Rx7d
1.N*3c 2.Sx3c 3.R1a+ 4.Kx1a 5.L*1c 6.K2b 7.L1b+
1.S1d 2.K2d 3.R2b+ 4.Kx1e 5.+R2e

1.P*6c

if 2.Sx6c, 3.Bx7c+

1.N4e

if 2.Px4e, 3.Bx3c+
1.N1a+ 2.Kx1a 3.L*1c 4.K2a 5.L1b+
1.N*2e 2.K1b 3.N*2d 4.Px2d 5.N1c+ 6.Kx1c 7.+B3a 8.K2c 9.+B2b

1.P*5b

if 2.Rx5b, 3.R2a+. if 2.Gx5b, 3.Bx5e

1.P*2d

there’s no way to prevent P2c+ for White.