2 White has only six pawns and the king, but move twice at each turn.
4 figure.diagram-container
6 | fen:rnbqkbnr/pppppppp/8/8/8/8/1PPPPPP1/4K3:
7 figcaption Standard deterministic position
10 The white army can appear much too small, but the power to move twice in a
11 row shouldn't be underestimated. At each turn white plays two moves
12 without any constraint. The goal is to capture the king.
14 figure.diagram-container
16 | fen:rbbknn1r/1p2pp1p/2p3qK/p2p2p1/2PPP3/8/5P2/8:
18 | fen:3rq3/1p4p1/1k1pKp2/3P1P1n/p7/5n2/8/8:
19 figcaption Left: not a checkmate! Right: a "Monster-checkmate".
22 | The diagram position on the left looks pretty much like a checkmate,
23 | but white can take the queen and come back to the h6 square. Finally,
24 | white can mate in an unusual way, like the following diagram found
25 a(href="https://en.wikipedia.org/wiki/Monster_chess") on Wikipedia
26 | . There is no way for the black king to avoid being captured since white
27 | plays twice (the threat is 2.d7,dxe8).
29 figure.diagram-container
31 | fen:4k3/8/4P3/8/3P4/8/2q5/7K:
33 | fen:4k3/8/3PP3/8/8/8/2q5/7K:
34 figcaption Left: before 1.d5,d6. Right: after this move:, it's checkmate.
39 | Ralph Betza analyses this variant and the double move on
40 a(href="https://www.chessvariants.com/d.betza/chessvar/muenster.html")
42 | . Four pawns thus seems too few. Eight would most likely be too much,
43 | so the games here start with six white pawns.
44 | With time or engine play it could be further adjusted (to 5 maybe?).
45 | Anyway, that the variant is playable
46 a(href="https://greenchess.net/rules.php?v=monster") on greenchess.net
47 | with any number of white pawns.