Study (Von Jaenisch 1792)

White: Kf6, Ng4,

Black: Kh8, a4, f7, g6, h7

Solution:   1. Nh6 – a3
                     2. Kxf7 – a2
                     3. Kf8 – a1=Q
                     4. Nf7  (Mate)

Study (Haga 1921)

White: Kb3, Qa8, Rf6, d3, f4, h5
Black: Kh7, Qd4, Rg7, b6, d5, g3
Solution:   1. Rh6+ – Kxh6(forced)
                     2. Qh8+ – Rh7
                     3. Qxd4 (gain)