Type 3: Mate by piece xy discovered by piece mn (White)
Da1e1 - Mate by Rook a1 discovered by King e1
Dc1e1 - Christoph Fieberg Retro Mailing List, Oct. 2, 2002 Mate by Bishop c1 discovered by King e1
SPG in 5,5 moves
[rnbq1bnr/ppppp2p/5pp1/6k1/3PK3/7Q/PPP1PPPP/RNB2BNR]
1.d4 f6 2.Qd3 Kf7 3.Qh3 Kg6 4.Kd2 Kg5 5.Ke3 g6 6.Ke4#
Dd1e1 - Noam D. Elkies Retro Mailing List, Oct. 2, 2002 Mate by Queen d1 discovered by King e1
[rnbq1bnr/pppp1ppp/4p3/4R3/6kP/4P1P1/PPPP1P2/RNBQKBN1]
1.h4 e6 2.Rh3 Ke7 3.Re3 Kf6 4.g3 Kf5 5.Re5+ Kg4 6.e3#
Df1e1 - Noam D. Elkies Retro Mailing List, Oct. 2, 2002 Mate by Bishop f1 discovered by King e1
[rnbq1bnr/ppp2ppp/3Q4/4p3/2k1P3/8/PPPP1PPP/RNBK1BNR]
1.e4 e5 2.Qg4 Ke7 3.Ke2 Kd6 4.Qxd7+ Kc5 5.Qd6+ Kc4 6.Kd1#
Dh1e1 - Mate by Rook h1 discovered by King e1