# zugzwang (forced)

A thing that must act when each action within its reach moves it nearer a wall, and not acting is the one action out of reach.

- Computed level: L14 (depth in the emergence graph, not abstraction)
- Status: published  ·  Domain: agency

## Emergence
**Emerges from:** [act](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-act.deed), [action](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-action.deed), [reach](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-reach.action), [motion](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-motion.movement), [near](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-near.spatial), [wall](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-wall.range-end), [window](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-window.range), [choice](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-choice.decision)

**Through:** The rules demand a move, so the null action that would hold the position is taken out of reach; each action left keeps the thing inside the window but nearer its wall. No single threat does the damage; the obligation to act does.

**Novel properties:**
- an obligation to act that is itself the wall
- a position that is safe only if left alone
- reach that is not empty and is worth less than none

## Examples
- In the chess position called a trebuchet, whichever side is to move must give up its pawn and loses, because the rules do not allow a player to pass. *(chess)*

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*Canonical: https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-zugzwang.forced*  
*Structured data: https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-zugzwang.forced.json*  
*Every definition provably resolves to space, time, energy and pattern.*