p.boxed
  | A piece 'A' captures an opponent piece 'B' if and only if B can take A
  | according to the orthodox rules.

figure.diagram-container
  .diagram
    | fen:r1bqkbnr/pppp1ppp/2n5/1B2p3/4P3/5N2/PPPP1PPP/RNBQK2R:
  figcaption After 3.Bb5?? black can play 3...Nxb5 or 3...e5xf3 for example

h3 End of the game

p Conforming to the rule, the king captures the pieces which are attacking him.

figure.diagram-container
  .diagram
    | fen:8/8/8/3r1k2/8/8/3K4/8:
  figcaption The white king can take the rook

p.
  However, the king is attacked in the same way as in regular chess -
  and it's the only exception.

figure.diagram-container
  .diagram
    | fen:r7/2n5/1q6/5k2/8/8/K7/8:
  figcaption.
    The king cannot take on a8 because the square is guarded by the knight:
    it's checkmate

h3 Source

p.
  | Very few resources about this variation: I found 
  a(href="http://play.chessvariants.org/erf/ZenChess.html") this webpage
  |  and 
  a(href="http://www.pathguy.com/chess/ZenChess.htm") this one
  | .

p Inventor: Moe Moss (1970)