Owen's Rules — Version 0.8.0

A playable local two-player prototype of a hidden-army chess game where the goal keeps changing. The rules are deliberately experimental.

This repository also holds Opening Arena, an interactive chess openings trainer, in openings/. See openings/README.md.

Play online: Owen's Rules · Opening Arena

The hosted game is still two players sharing one device. Opening the link on separate devices starts separate games; there is no network multiplayer or saved-game synchronization.

Run

Install Node.js 20 or later, then from this directory:

npm start

Open http://localhost:5173 for Owen's Rules, or http://localhost:5173/openings/ for Opening Arena. There are no packages to install, build steps, accounts, external fonts, or network services. The server binds to your computer's loopback interface. To choose another port: PORT=5174 npm start.

npm test       # Rule tests, seeded simulated play, and the Opening Arena tests
npm run check  # Entry-point syntax checks plus the tests
npm run build  # Copy browser assets into dist/ for static hosting

Play

1. Player 1 occupies a1–d4, and Player 2 occupies a5–d8. Both armies are shuffled and face down. Files e–h begin empty.
2. Select an outlined hidden tile, then choose a highlighted destination: 1–4 squares right, 1 square forward, or 1 square left. The entire path and destination must be empty; there is no jumping or capture. Flip where it lands. The whole slide and reveal costs one action, regardless of distance or the piece underneath. Forward is toward rank 8 for Player 1 and rank 1 for Player 2. A pawn revealed on its far rank promotes to a queen.
3. Fast start: each player's first turn has 3 actions and their second has 2. After that, turns have 1 action. Both can be changed in Playtest rules. The action keeper under the board shows a token for each action this turn; spent ones turn into empty slots, and a Sugar Rush adds a token.
4. Turns switch immediately, so the next player can act without dismissing a popup. On later turns, reveal another tile or use a revealed piece's chess movement. Clearing a square can open new reveal routes for nearby hidden tiles.
5. Attack a hidden enemy to challenge it: the target flips in place, and the attacker stays put. Kings are never captured. Newly exposed kings in check receive a response action.
6. Any of your pieces except the king can Stack with another of yours. See Owen's Rules below.
7. Win by collecting Owen's crowns, or by checkmate. How to play explains the current rules; Playtest rules changes selected rules when starting a fresh game.

Use mouse/touch, or Tab to enter the board, arrow keys to navigate, and Enter/Space to select. Escape clears a tile selection. The Pass-device screen between turns checkbox is off by default. Enable it at any point if you want the board hidden between players; when enabled, the next player presses a ready button. This changes presentation only, not turn costs or game state.

Games live in memory. Refreshing or restarting reshuffles the armies. There is no AI opponent, online play, persistence, or undo. The browser holds the full state internally; this is a shared-device prototype, not a secure online hidden-information server.

One bonus reveal per turn

The independent One bonus reveal per turn toggle in Playtest rules is off by default. When enabled, finishing your normal action(s) offers one optional free slide-and-reveal of another hidden tile, followed by the opponent's turn. The board highlights eligible tiles and offers Skip bonus reveal inline, without a popup. If no legal reveal exists, the turn ends automatically.

The normal action can itself be a reveal, so a one-action turn can uncover two tiles. The bonus cannot move a revealed piece, capture, challenge, stack, or unstack. Its newly revealed piece cannot take another normal action that turn. Check still ends a turn immediately; a king revealed in check still receives its response, and response actions never earn bonuses. Ending a multi-action turn early also declines the bonus.

The bonus is once per turn, even with two or three normal actions. Slide-and-reveal is free (unlimited) supersedes it; that setting disables the bonus checkbox while retaining its choice. Applying playtest settings starts a new game, and New game retains the rules. Queen movement remains unchanged.

Owen's Rules (Version 0.6)

The original game was invented by a 4-year-old, so the way to win keeps changing. Owen's Rules is the only game mode.

• Goals. Owen picks one of 13 goals, such as Sleepover! (4 pieces in the other team's half), Parade Time (6 pieces on one row), Snack Attack (eat 8 points of pieces), or Hug the Board (touch all four edges). Finishing it earns a crown, and Owen picks a new goal. First to 3 crowns wins. Checkmate still wins instantly.

• Owen gets bored. After 12 turns he swaps the goal. The countdown is always shown.

• "No! You play like this!" When someone is one step away, each time the turn passes there is a 40% chance Owen changes the goal.

• Not Fair tokens. If a goal is taken away while you are one step from finishing it, you get a token (maximum 3). Spend one per turn, for free: Not fair! draws a new goal, and Pinky promise locks the goal until your next turn ends.

• Fairness guardrails. Owen never picks a goal someone has already nearly finished. Goals marked counts from now start both players at zero. Progress reads only public information.

• Captures pay off. Captured pieces fly into your Toy Box. Catching anything bigger than a pawn gives a Sugar Rush: one extra action right away, once per turn. Giving check still ends the turn, and king responses never earn one. Every 4 toys earns a Not Fair token.

• Unicorns. Every knight is a unicorn: the same knight piece, with a horn. It still moves exactly like a knight.

• Stack anything. Any of your pieces except the king can stack with another of yours up to 2 squares away, up to 3 high. Select a piece, then click a piece marked +. Your first stack each turn is free, so you can use the new stack right away.

• Every stack spins the power slots. A stack moves like all of its pieces combined (a pawn inside steps one square any way), plus a power. Each time you stack, three slot reels spin and land on a power, so the same mix can get a different power next time. Powers on the normal reel: Bouncy, Froggy, Floaty, Ghosty, Fort (can't be captured), and Sticky (freezes touching enemies). The Power reels panel shows every reel.

• Toys, super spins and jackpots. Stacking a toy from your Toy Box onto one of your pieces spins the wild reel: Swappy, Sneezy (pushes touching enemies away), Pew Pew (zaps 2 squares away), Ghosty, Floaty and Bouncy. Stacking a third piece on top spins the : Choo-Choo (slides like a rook), Rainbow Unicorn (one or two unicorn hops), Wizard (teleports to any empty square of its color), Castle Crusher (slides like a rook through pieces) and Mega (also moves like a queen). Three of a kind always hits its jackpot: 🚂 pawns, 🌈 unicorns, 🧙 bishops, 🏰 rooks, 💥 queens. removes your own top piece and spins the normal reel again for what's left; toys stay stuck on. A captured stack comes apart into separate toys.

Each attacker has its own capture sprite: the pawn waddles in for a CHOMP!, the unicorn hops for a NEIGH!, the bishop teleports with a ZAP!, the rook slams for a CRASH! that shakes the board, the queen spins in for a KAPOW!, the king stomps for a BONK!, and a pawn stack does a SQUISH!. The captured piece pops out and flies into the Toy Box. Reward bubbles show Sugar Rushes and new tokens.

Announcements pop up over the board without blocking it. Goal cards flip in, progress bars grow, crowns and tokens pop, the countdown yawns, and a near-complete bar shakes. Moving tiles slide to their squares, reveals slide and then flip, and captures flash. The tuning values live in rules.chaos (crownsToWin, boredTurns, nuhUhChance, maxTokens).

Architecture

File	Responsibility
src/engine.js	Immutable transitions, legal actions, response scheduling, public-only UI projection
src/board.js	Coordinates, geometry, player direction
src/rules/config.js	Default values and configuration validation
src/rules/setup.js	Army composition, independent shuffles, starting squares
src/rules/exposure.js	Clear reveal paths, direction and distance profiles, isolated exposure definition
src/rules/movement.js	Per-piece movement registry and attack geometry
src/rules/pawn-stack.js	Combine, split, eight-direction movement, optional step/scout action variants
src/rules/king.js	Check and newly exposed king detection
src/rules/turn.js	Action costs and turn allowance
src/rules/outcome.js	Checkmate, stalemate, repetition, and quiet-action draws
src/rules/chaos.js	Owen's Rules: goal deck, crowns, boredom, "No! You play like this!", Not Fair tokens, capture rewards
src/rules/powers.js	Owen's stacks: any-piece stacking, Toy Box toys, the power reels, power geometry and power actions
src/rules/random.js	Seeded randomness stored in the game state
src/main.js	DOM rendering and input; no movement-rule implementations. Every game starts with chaos.enabled, since Owen's Rules is the only mode
tests/engine.test.js	Rule scenarios, privacy invariants, and material conservation
tests/exposure.test.js	Reveal distances, blockers, player directions, promotion, privacy and king responses
tests/stack-experiments.test.js	All eight experiment combinations, compound actions, scouting privacy and king responses
tests/owen-stacks.test.js	Any-piece stacks, free first stack, reel spins, super spins, jackpots, toys, pop-off and every special power

The engine exports createGame(overrides, random), getLegalActions(state), applyAction(state, action), and publicView(state). All actions are validated by the engine. applyAction returns a new state and never mutates the supplied one. An injectable random function supports deterministic tests.

Examples of code-level experiments:

createGame({
  turn: { actionsPerTurn: 2, revealCostsAction: false },
  exposure: { mode: 'flexible', rightRange: 4, leftRange: 1, forwardRange: 1 },
  stack: { enabled: true, anyAdjacent: true, stackAndStep: true, scouting: true }
});

The engine still supports the classic checkmate-only rules and the pawn stack experiments (chaos.enabled: false), and the tests cover them, but the UI only offers Owen's Rules. The UI exposes the opening-move profiles, turn options, and a stacking toggle. The new opening is the default; the two classic one-square opening profiles remain selectable in Playtest rules. Custom reveal ranges are configurable in code (0 disables a direction). More substantial rule changes belong in the small rule modules, not in the rendering code. For example, change revealDestinations to try another exposure definition, or stackMoves and stackAttacks together to try another stack movement pattern. The old forwardCapture and leap configuration flags have been removed.

See DESIGN_NOTES.md for exact assumptions, unresolved questions, and playtest priorities.

Hosting and updates

The GitHub repository is Kirkmanamos/owen-chess. GitHub Pages publishes the dist/ artifact through .github/workflows/pages.yml. Every push to main runs the checks, builds the site, and deploys it; pull requests run checks and build without deploying.

To publish an update, commit the intended files and push main, then check the Test and publish game workflow in GitHub Actions. Browser asset paths are relative so the game works both at localhost and under /owen-chess/. Only index.html, src/, openings/ (without its README and sound lab), and .nojekyll are included in the hosted site. Local screenshots and playtest records in artifacts/ are ignored by Git.

The hosted link works without running the local server. For local development, use npm start and the localhost URL rather than opening index.html directly.