Hidden rank capture
Protect an immobile flag while revealing ranks only when pieces meet.
Logic & rule checking
- Players
- 2
- Time
- 15–25 minutes
- Materials
- 4×4 grid; each side flag 0 and ranks 1,2,3 with opaque backs
Prepare
Each privately places its four labeled pieces on its own home row: W row 1, B row 4, one per column. Flag 0 cannot move; ranks 1,2,3 can. Owners may inspect their own faces. Every back shows its owner but hides its rank.
Play
Alternate moving one non-flag piece one orthogonal step. An empty destination is a normal move. A friendly destination is illegal. Attacking an enemy reveals both faces; higher numbered rank survives on the destination and lower is removed. Equal ranks both disappear.
Worked example
Any attacking non-flag captures an enemy flag and wins immediately. The flag never attacks. There is no special weakest-beats-strongest rule, diagonal motion, jumping or resurrection.
Finish and check
For a practice encounter W2 at B2 attacks B1 at B3: W2 survives at B3. If both are rank 2, both are removed and B3 becomes empty. Keep revealed survivors face up for the rest of play; their rank is now public.
Adaptation and limits
If a player has no movable pieces left, that player loses unless the opponent is also immobile, in which case draw. At 40 total moves without a captured flag, draw. Write the private home arrangement before starting so owners cannot secretly exchange ranks during play; reveal it for the final audit.
Purpose, observation and provenance
Within this activity: Protect an immobile flag while revealing ranks only when pieces meet.
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
- Each privately places its four labeled pieces on its own home row: W row 1, B row 4, one per column. Flag 0 cannot move; ranks 1,2,3 can. Owners may inspect their own faces. Every back shows its owner but hides its rank.
- Alternate moving one non-flag piece one orthogonal step. An empty destination is a normal move. A friendly destination is illegal. Attacking an enemy reveals both faces; higher numbered rank survives on the destination and lower is removed. Equal ranks both disappear.
- Any attacking non-flag captures an enemy flag and wins immediately. The flag never attacks. There is no special weakest-beats-strongest rule, diagonal motion, jumping or resurrection.
- For a practice encounter W2 at B2 attacks B1 at B3: W2 survives at B3. If both are rank 2, both are removed and B3 becomes empty. Keep revealed survivors face up for the rest of play; their rank is now public.
- If a player has no movable pieces left, that player loses unless the opponent is also immobile, in which case draw. At 40 total moves without a captured flag, draw. Write the private home arrangement before starting so owners cannot secretly exchange ranks during play; reveal it for the final audit.
Hidden rank capture — player materials
Back each piece with opaque paper showing only W or B. Keep two private home-row logs; show revealed survivors face up.
| Private row | A | B | C | D |
|---|---|---|---|---|
| W1 | ||||
| B4 |
| Move | Attacker/defender revealed | Survivor / removals |
|---|---|---|
| ________ | ________ | ________ |
| ________ | ________ | ________ |
| ________ | ________ | ________ |
| ________ | ________ | ________ |
| ________ | ________ | ________ |
| ________ | ________ | ________ |
| ________ | ________ | ________ |
| ________ | ________ | ________ |
| ________ | ________ | ________ |
| ________ | ________ | ________ |
Host check — keep separate
Rank 2 beats 1; equal ranks both disappear; any moving rank captures flag 0.
Examples are stipulated model cases, not measured experimental or learning outcomes.
Related activities
Activity library · Grid fleet search — Free Printable PDF & Rules