Answer to Problem: "Give and Take Key" - has a compensating factor. One flight may be
given and another taken away; pin or unpin of White may simultaneously involve pin or unpin of
Black; the Key piece may move from one position in which it is subject to capture to another.
1. Be7 (threat is 2. Qf8 mate) 1 ... c6+ 2. Bd6++ (Cross-check theme, or Interference motif)
1 ... c5+ 2. Rg3++ (Cross-check theme, or Interference motif. 1 ... c5+ allows a Line-opening
for the R on b7 to protect the B on e7)
1 ... Kxe7 2. Re6++ (Rook and Bishop battery)
1 ... Be8 2. Qe6++ (The Black B creates a self-block)
Problems are from "101 Chess Problems for Beginners" by Comins Mansfield and Brian Harley, and edited by Fred Reinfeld.
