Declare together. Predict the move. Hunt the resting king.
Version 1.0.3G · Alleycat Alpha 0.7
Load a manually saved KINGSLAY game file.
Play the computer or another person on this device.
For Human vs AI, the selected star level loads an Alpha 0.7 preset. AI-vs-AI has independent Alpha 0.7 controls above.
KINGSLAY starts from a standard chess position, and all pieces move as they do in chess. Two things change everything: both players move at the same time, and a piece that moves must rest on the next turn.
You win by capturing the enemy King or checkmating it.
Use this section when simultaneous movement creates an unusual situation.
Retaliation after a King dies
If a King is captured while the surviving King is still in check, play continues only while that check remains. The survivor must respond to that check like any other. If the survivor becomes safe, the original Kingslay is final.
These rules are valid but extremely rare in practice.
True stalemate is extremely rare. It occurs only when a player has no legal move at all: every piece is physically blocked by board edges and friendly pieces. Attacked squares alone never block a move. Result: Draw.
Other rare draws, such as repetition or the move-count limit, are referee rules and do not need to be learned before playing.
Declare together. Predict the move. Hunt the resting king.
This is the detailed reference. The Learn screen intentionally stays short; this handbook keeps the fuller rules, unusual terminal states, strategy, engine concepts, and edge cases.
KINGSLAY uses the normal chess board, starting position, pieces, and ordinary movement geometry, but replaces alternating turns with simultaneous declaration. Both players commit before either learns what the other declared.
The game begins from the standard 8×8 chess starting position. Players are expected to already know ordinary chess piece movement, captures, castling, promotion, check, and basic checkmate. KINGSLAY changes how the two declared moves interact and what happens after a piece moves.
If the movers choose different destinations and do not otherwise interfere, both moves occur. A mover captures an enemy occupant only if that enemy remained on the destination.
If the target simultaneously moves away, it is not captured. The attacker still travels to its declared destination if it survives.
If opposing movers choose the same destination square, they collide and both are removed. If a king is one of those movers, that king is physically slain.
After collision handling, a surviving mover captures an enemy occupant that stayed on its destination and then lands there.
Castling is one declaration containing both the king move and rook move; both pieces count as movers and rest if they survive.
Every surviving piece that moved in the preceding joint turn is ineligible to move on the next declaration. After that next resolution, it becomes active again if it survives.
| State | Can move? | Still attacks/blocks? | Can be captured? |
|---|---|---|---|
| Active | Yes | Yes | Yes |
| Resting | No | Yes | Yes |
A king may declare a move into geometry that is attacked before resolution. The attacking piece may simultaneously move away, collide, or cease to attack that square. King safety is judged after the joint resolution.
That side must make a declaration that services the check. An unrelated plan is unavailable unless the declaration itself resolves the check. This can temporarily constrain the whole army.
A resting piece still gives check geometrically but cannot make a new move or capture declaration on that beat.
If both living kings are checked at the same checkpoint, the position enters crossing-check freedom; the ordinary one-sided check-response restriction is suspended and both sides may use eligible declarations, including counter-Kingslay attempts.
| Result | Meaning | OA score |
|---|---|---|
| Kingslay | The opposing king is physically slain, or an executable active checker has an immediate forced king capture. | +2 / −2 |
| Checkmate | A living king is in unresolvable check but the immediate physical capture is not executable under the current rest/geometry state. | +1 / −1 |
| Kingslay-Checkmate | A king has been slain while the surviving king remains in a terminal retaliation/checkmate closure. | treated as Checkmate |
| DoubleKingslay | Both kings are slain in the same resolution or equivalent retaliation sequence. | 0 / draw |
| Other draws | Repetition, physical stalemate, fifty-joint-turn, or other referee draw. | 0 |
A king can be physically removed by a stationary strike or destination collision involving the king.
If a checked king has no legal response and an active checker can execute the capture, the referee can classify the position as an immediate forced king kill.
If one king is physically slain while the surviving king remains under continuous check, a narrow closure/retaliation sequence may continue so the simultaneous consequence is resolved correctly.
Uses the standard king/rook destinations and requires the king and rook to be unmoved and active, the king not currently checked, the path clear, and the crossing/destination squares not geometrically attacked at declaration time. Both surviving movers rest.
A surviving pawn double-step creates the one-turn vulnerability. The capture is destination-first: the attacking pawn must survive landing before the vulnerable pawn is removed.
A pawn promotes only if it survives landing on the promotion rank. Human choices are queen, rook, bishop, or knight.
| Marking | Meaning |
|---|---|
| Blue R | Resting piece; cannot move this declaration. |
| Last-move highlights | Squares involved in the previous joint turn. |
| Locked declaration | Your chosen move while the opponent/AI is still deciding. |
| FROM marker / destination cue | Shows where the opponent's just-revealed move began and ended. |
| Red check marking/banner | A living king is currently checked. |
| Previous / Forward | Review historical board states without changing the live game. |
| Undo last turn | Actually rewinds the last joint turn so it can be replayed. |
White declares a capture of a Black rook while Black moves the rook away. The capture misses; White's mover lands on the rook's old square and rests if it survives.
White and Black declare moves to the same destination. The opposing movers collide; neither claims a normal capture.
A piece moves and gives check after resolution. On the next declaration that checker is resting. It still attacks the king, but cannot itself move to capture the king on that beat; the checked side must still service the check.
Ordinary chess asks what the opponent can do next. Crossbeat asks what the opponent is declaring at the same time and what board those two intentions jointly create. The basic unit of analysis is a joint outcome, not an isolated move.
Every move is a commitment because the mover becomes unavailable on the following declaration. A landing square must be judged together with the fact that the piece will be frozen there for one beat.
When a piece is attacked, the defender can flee or hold; the attacker can attack or decline. Those combinations produce different joint worlds. Strong play includes second-order thinking: if the opponent knows you expect a flee, they may hold; if you expect that adjustment, you may change again.
| Attacker | Defender | Typical interpretation |
|---|---|---|
| Attack | Hold | Attack lands; tactical confrontation. |
| Attack | Flee | Attack may miss; attacker may rest awkwardly. |
| Decline | Hold | Defender calls the bluff. |
| Decline | Flee | Defender gives ground without being hit. |
A singly checked side must service its king, so unrelated pieces may be unable to flee or counterattack. The opponent can use that tempo to build forks, double attacks, or attacks on pieces that are effectively unavailable while check is serviced.
A king may survive the current resolution but land somewhere that becomes attackable on the next beat while the king itself is resting. Evaluate both immediate joint-resolution survival and next-beat targetability.
Normal chess material values are a useful starting point, but rest changes exchange value. A rook that must rest on an attacked square may be worth less than its nominal value; a pawn can be unusually important if its attack geometry hits a resting major.
Opening: development, center influence, and king safety still matter, but orthodox sequences do not transfer cleanly. Middlegame: prediction, resting exposure, checks, and conditional attacks dominate. Endgame: fewer pieces make exact joint interactions easier to calculate, while resting kings and advanced pawns become proportionally more important.
Crossbeat Referee 2.0.12 generates legal declarations, resolves simultaneous moves, tracks rest, checks, special moves, terminal states, repetition, and scoring. Engines do not decide legality; they evaluate the legal possibilities the referee gives them.
The Cat-family framework can pair every candidate SELF declaration with opponent declarations and ask the referee to resolve each pair exactly. Each cell is a concrete joint outcome followed by evaluation. Selective tactical continuations are added where an architecture specifically calls for them rather than blindly building a broad game tree from every cell.
The Cat architecture uses roughly one pawn as the basic nonterminal evaluation unit. Material, resting exposure, king pressure, cages, and related terms share that scale. Kingslay is represented by a large fixed terminal anchor in analysis; checkmate is separately valued.
A simultaneous game cannot evaluate a declaration against only one guessed reply. Engines can maintain distributions over SELF and opponent declarations. Cat solvers retain legal opponent support through a protected floor so a severe response cannot disappear merely because its modeled probability becomes small.
InGenie is the second major KINGSLAY engine lineage, descended from the earlier Engine A/B/C experiments and the “Engine E → InGenie” line. Its versions developed progressively richer opponent-response, Bayesian coupling, support reopening, rest-horizon, exchange-settlement, and safety machinery. I11L 1.1.5L and InGenie 2.0L remain important competitive references rather than obsolete predecessors.
ALLEYCAT 1.0 is the sealed pure one-ply Cat benchmark. Blackcat adds bounded Crossbeat-specific structural compensation such as king-cage pressure, queen-cage/pin pressure, cage relay, and advanced/passed-pawn emphasis.
Cougar builds on Blackcat and adds Kingslay-oriented objectives plus a lazy post-selection verification layer. The normal policy proposes a move; only the sampled candidate receives the more expensive audit.
For a sampled king move, Cougar checks legal opponent declarations against the resulting king destination. Executable active/discovered attacks can publish severe structural downside; resting checkers are treated differently because they may check without being able to execute the capture immediately.
For a sampled non-king move, Cougar can check whether the mover will rest where a smaller active enemy can capture it, and can test bounded evacuation when a move exposes a larger active friendly piece.
If verification materially lowers the sampled move, Cougar can reject it and perform a deterministic seeded redraw from the remaining policy.
Cat D 0.1.2 is a stronger experimental Cat verification branch. It adds bounds-oriented viability pruning, bounded tactical settlement, unresolved lower-bound/mean penalties, a strict roughly two-pawn final selection band, and a deterministic post-selection credibility gate. It is much better at refusing moves it already knows are bad, while still being vulnerable when the evaluator fails to recognize a threat in the first place.
Engine randomness is deliberately reproducible. Seeded CounterRNG derives choices from the engine's own seed and color-neutral calculation context rather than uncontrolled browser randomness. This makes suspicious moves reproducible for diagnostics and regression testing.
Diagnostic records can preserve exact before/after states, declarations, captures, collisions, check/rest state, selected ranks/probabilities, convergence, verification, and timing. These records feed permanent regression fixtures so fixed failures become pass gates rather than disappearing from memory.
Every new computer game uses Alleycat 2.0 Alpha 0.7. Difficulty changes only its parameters: the share of its own legal declarations evaluated, final-selection temperature, and—in the two easiest presets—the probability of a uniform random declaration. Opponent modeling remains at full visibility. The Kitten name identifies the one-star Alpha 0.7 learning preset; it is not a separate engine. Older engine implementations remain embedded only so historical saves and reviews can still be interpreted.
Current research uses a support-first view of uncertainty: a candidate declaration can have a lower bound, central expectation, and upper bound across still-feasible joint outcomes. A legal low-probability branch can still determine a hard structural bound.
Strategic modes can be treated as constraints on the feasible joint-outcome state space. Conditioning on a mode removes incompatible worlds and can only tighten support-based bounds. Current terminology also distinguishes risky versus conservative behavior and multimodal/Bluffing States where coherent strategic regimes produce meaningfully separated outcomes.
The development process increasingly uses saved difficult positions, exact replay, fresh-seed continuation tournaments, and an Evaluation Forensics Analyzer. The goal is to find cheap features that prevent large evaluation collapses rather than solving every problem with generic deeper search.
KINGSLAY is suited to open engine competition because rules can remain fixed while engines differ in prediction, risk, probability modeling, search, and evaluation. A future public interface could accept a serialized state plus legal-action list and return a declaration. Human ratings should remain separate from engine evaluation values and match-point scoring.
| Situation | Referee behavior |
|---|---|
| Both kings physically slain in one resolution | DoubleKingslay — draw. |
| One king slain while surviving king remains checked | Retaliation/closure remains alive until continuous check is resolved or terminal. |
| Both living kings checked | Crossing-check freedom. |
| Checked king has no response; active checker can execute capture | Forced Kingslay. |
| Checked king has no response; immediate capture not executable | Checkmate. |
| King/rest state yields no ordinary declaration | Referee may supply the required Stand Still declaration. |
| Three identical full states | Threefold repetition draw. |
| Fifty-joint-turn threshold reached | Draw. |
Move notation is close to coordinate chess notation. Piece letters are N, B, R, Q, and K; pawns have no piece prefix. Joint-turn records show both declarations together.
| Term | Meaning |
|---|---|
| Joint turn | One pair of declarations and one simultaneous resolution. |
| Resting | Moved last joint turn; cannot move this declaration but still exerts geometry. |
| Collision | Opposing movers choose the same destination and are both removed. |
| Stationary strike | A surviving mover captures an enemy occupant that did not move away. |
| Kingslay | Physical king death or immediate forced king capture by an executable active checker. |
| Checkmate | Unresolvable check without an executable immediate king capture. |
| Crossing check | Both living kings are checked at the same checkpoint. |
| Closure | Referee state used to finish unusual king-death/check sequences correctly. |
| Policy | An engine probability distribution over candidate declarations. |
| Protected floor | Minimum opponent-response probability used so legal threats remain represented. |
| Structural lower bound | Worst still-feasible evaluated outcome regardless of modeled probability. |
| Executioner | Cougar's selected-move verification/reject-redraw layer. |
| Bluffing/strategic mode | A coherent regime or event constraint that removes incompatible joint outcomes. |
This embedded handbook is restored from the mature Handbook v1.0 / Referee 2.0.12 documentation and updated for the current 1.0.3G presentation and engine selection. The referee remains 2.0.12. UI/difficulty descriptions may evolve without changing the underlying game rules.
1.0.3G restores the reviewed player Rules & Clarifications page. The 1.0.3F roster/settings repair was accidentally built on an older Learn-page baseline. This release restores the approved simplified page—including Basic Rules, Clarifications & Edge Cases, Special Moves, Endings, retaliation after a King dies, and Rare Rules—without changing Referee 2.0.12, the corrected Alpha 0.7 softmax, the Alleycat-only new-game roster, or Settings navigation.
1.0.3F completed the Alpha 0.7 replacement. Every new Human-vs-AI and AI-vs-AI game exposes Alleycat 2.0 Alpha 0.7 as the sole opponent. Easiest through Most Difficult are parameter presets of that one engine. Legacy engines are hidden and retained only for historical save/review compatibility. Full Documentation and What Changed moved from Home into Settings.
P(move) / P(best) = exp(-deficit / T). Earlier coupled probability mass no longer keeps a clearly inferior move artificially alive at execution.1.0.3E introduced Alpha 0.7 but mistakenly preserved the old opponent pools and Home navigation. Version 1.0.3F corrects that regression.
1.0.3D was the combined engine-pack and random-selector branch. Live play uses Referee 2.0.12 and embeds the retained legacy/InGenie engines, current Cat architecture, ordinary Random (R), and Safe Random (SR). Existing 1.0.3D controls are preserved; SR support is present in the backend but is not yet exposed in the interface.
KINGSLAY 1.0.2 is the maintenance branch from the frozen KINGSLAY 1.0 interface. It preserves Crossbeat Referee 2.0.12 and established engine behavior while consolidating the UI regression repairs and usability fixes found during testing and KELO calibration work.
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