H#4: The mate is delivered from a square controlled by two pinned black pieces.
⧖ A thematic tournament featuring this idea was announced by Heinz Brixi (Austria, 1876–1952) in the Deutsche Schachblätter in 1927 or 1928.
See also: Pin-mate.
Fox, Charles Masson
Deutsche Schachblätter, Brixi TT, 1928
1st Prize
1.Rd6
f6
2.Qc4
f7
3.Kd4
f8=S
4.Kc5
Se6#
Brixi, Heinz
Jána, Josef
Deutsche Schachblätter, Brixi TT, 1928
2nd Prize
1.c3
Rh1
2.cxb2
Bc3
3.bxa1=S
Rb8+
4.Sg8
Bxf6#