Predator and prey placement
Compare a single capturing mover with a team that first places its pieces.
Logic & rule checking
- Players
- 2
- Time
- 15–25 minutes
- Materials
- 5×5 grid; one predator and eight prey
Prepare
The predator starts C3. All eight prey begin off board. Prey acts first, and the two sides alternate. Only orthogonal neighbours are connected; diagonal movement never applies.
Play
While any prey remain in reserve, prey’s turn places one on an empty cell. After all eight have been placed, prey’s turn moves one prey one orthogonal step into an empty cell. Prey never jumps or captures. Captured prey stay out of play and are not put back in reserve.
Worked example
The predator either steps one orthogonal cell to empty space or jumps over one adjacent prey to the immediately following empty cell, removing that prey. One jump only per turn; captures are optional. Two consecutive prey block a jump.
Finish and check
Practice example: predator C3, prey C4, empty C5 permits C3→C5 capturing C4. If C5 is occupied it is illegal. This example does not change the real starting reserves or make unplaced prey count as captured.
Adaptation and limits
The predator wins on its third capture. Prey wins when the predator has no legal step or jump at the start of its turn. If neither happens after 40 predator turns, draw. Record reserves, captures and current positions separately so placement and movement phases cannot be confused.
Purpose, observation and provenance
Within this activity: Compare a single capturing mover with a team that first places its pieces.
A partner can replay each legal action and explain the stopping condition; this is an observable task, not evidence of lasting improvement.
Our rules, examples and printable diagrams are separately prepared. The earliest inventor of the broader mechanism is not established here.
Free alternative: Copy the supplied grids, labels and cards onto reused paper. No specialist product is needed. Adults may prepare pieces or act as a scribe.
Printable materials
Preview at 100% scale, with browser headers and footers off. Cut with suitable help. Keep host keys separate. This is a manual tabletop kit, not an online opponent, automatic judge or solver.
Rules to keep beside the materials
- The predator starts C3. All eight prey begin off board. Prey acts first, and the two sides alternate. Only orthogonal neighbours are connected; diagonal movement never applies.
- While any prey remain in reserve, prey’s turn places one on an empty cell. After all eight have been placed, prey’s turn moves one prey one orthogonal step into an empty cell. Prey never jumps or captures. Captured prey stay out of play and are not put back in reserve.
- The predator either steps one orthogonal cell to empty space or jumps over one adjacent prey to the immediately following empty cell, removing that prey. One jump only per turn; captures are optional. Two consecutive prey block a jump.
- Practice example: predator C3, prey C4, empty C5 permits C3→C5 capturing C4. If C5 is occupied it is illegal. This example does not change the real starting reserves or make unplaced prey count as captured.
- The predator wins on its third capture. Prey wins when the predator has no legal step or jump at the start of its turn. If neither happens after 40 predator turns, draw. Record reserves, captures and current positions separately so placement and movement phases cannot be confused.
Predator and prey placement — player materials
| Predator turn1–40 | Prey reserve | Prey placed/moved | Predator move/capture |
|---|---|---|---|
| ________ | ________ | ________ | ________ |
| ________ | ________ | ________ | ________ |
| ________ | ________ | ________ | ________ |
| ________ | ________ | ________ | ________ |
| ________ | ________ | ________ | ________ |
| ________ | ________ | ________ | ________ |
| ________ | ________ | ________ | ________ |
| ________ | ________ | ________ | ________ |
| ________ | ________ | ________ | ________ |
| ________ | ________ | ________ | ________ |
Host check — keep separate
C3 over C4 to empty C5 captures one; prey never re-enters reserve.
Examples are stipulated model cases, not measured experimental or learning outcomes.