Initial positionJump Sturdy is a simple game of breakthrough and race, with a very unusual twist. Although the pieces in the diagrams show additional pictograms for clarity, playing with unmarked checkers is far more convenient.

Object
The first player to have a man reach one of the of six squares of the opponent's back rank wins the game.
Alternatively, capturing all the opponent's men or blocking an opponent completely also constitutes a win.

Rules
The diagram shows the board with the men in the initial position. There are two players, white and black. White moves first after which turns alternate. Moving is compulsory.

Pieces
Although stacked doubles appear in the game, these do not constitute one piece, but two separate men. The top man can move, capture and be captured, the bottom man cannot, at least not as long as it is buried under another man.

Keeping this in mind, these singles and doubles may appear in Jump Sturdy:

pieces
single whitesingle blackdouble whitedouble blackmixed whitemixed black

Initial positionMovement and capture by single men
Consider a single man like the one on D6 as a chess pawn with additional sideways movement: it moves one square straight, not backwards, and captures diagonally forwards, as indicated.
All capture is by replacement. If the target is an opponent's double, only the top man is captured.

Two types of move are allowed:
  • To a vacant square
  • To a square occupied by a like colored single, making a double
Two types of capture are allowed:
  • Capture of an opponent's single
  • Capture of the top man of an opponent's double, regardless of its composition

The man on B2 may move to A2 but not to A3 or B3. It may capture the man on C3 or move to C2 to create a double.
The man on F3 may not move sideways, but it may move straight forwards to create a double, or capture the top man on E4, creating a mixed white, or the top man on G4, creating a double.

Initial positionMovement and capture by top men of doubles
Top men of doubles move and capture as chess knights, but only in a forwards direction. If they move or capture they leave the bottom man behind. This bottom man may be of either color.

Two types of move are allowed:
  • To a vacant square
  • To a square occupied by a like colored single, making a double
Two types of capture are allowed:
  • Capture of an opponent's single
  • Capture of the top man of an opponent's double, regardless of its composition

The top man on C4 may move to A5 or move to B6 to create a double. In either case it sets free the black bottom man on C4. It may not move to D6 or E5.
The top man on G2 may capture the man on E3, or the top man on F4, creating a double, or the top man on H4, creating a mixed white. In all cases the white bottom man on G2 is set free.

Tactics
One remark on tactics: if a single attacks a uniform double, it cannot be captured by its top man. But if the top man moves, it exposes the bottom man.
If a single attacks a mixed double, it cannot be captured by its top man either, and it covers the bottom man if the top man moves. In short: attacking doubles with singles is usually good.

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How I invented ... Jump Sturdy
Using the Jump Sturdy applet
External links


Jump Sturdy © MindSports
Java applet © Ed van Zon