p.boxed
  | The king moves like a knight, and the knights like a king.
  | The goal is still to checkmate the king.

p "Knights moving like a king" are quite logically called "commoners".

p Castling is still permitted, under the same conditions as in orthodox chess.

figure.diagram-container
  .diagram.diag12
    | fen:7k/8/8/8/8/1r6/8/3K1r2:
  .diagram.diag22
    | fen:rcbqk1cr/pppp1ppp/8/2b1p3/2B1P3/5Q2/PPPP1PPP/RCB1K1CR:
  figcaption.
    Left: Royal knight version of the two-rooks mate.
    Right: After 1.e4 e5 2.Bc4 Bc5 3.Qf3

p.
  On the right diagram, the threat is 4.Bxf7+ Cxf7 5.Qxf7+,
  with more material and a winning attack.

h3 Source

p
  a(href="https://www.chessvariants.com/diffobjective.dir/knightmate.html") 
    | Knightmate Chess
  |  on chessvariants.com.
  | This variant is also playable 
  a(href="https://greenchess.net/rules.php?v=knightmate") on greenchess.net
  | .

p Inventor: Bruce Zimov (1972)