LCN Examples

Essential format patterns for Location Condition Notation v1.0.0.

Enemy Evaluation Context

Important: The "enemy" keyword requires an evaluation perspective to determine which pieces are considered enemy pieces.

Standard Interpretation: In the Sashité ecosystem, "enemy" is typically evaluated from the active player’s perspective (the player whose turn it is to move):

"enemy": A piece belonging to the inactive player (opponent of the active player)
Not "enemy": A piece belonging to the active player
"empty": An unoccupied location (distinct from enemy/ally considerations)

This evaluation is independent of which piece is moving. The consuming specification (e.g., GGN) must provide the active player context for correct evaluation.

Basic Keywords

Empty Keyword

{
  "b2": "empty",
  "c3": "empty"
}

Specifies locations with the "empty" state constraint.

Enemy Keyword

{
  "e5": "enemy"
}

Specifies a location with the "enemy" state constraint (evaluated from active player’s perspective).

QPI Identifiers

Specific Piece Constraints

{
  "h1": "C:+R",
  "e1": "C:+K"
}

Specifies exact piece requirements using QPI identifiers.

Mixed State Values

{
  "f1": "empty",
  "g1": "empty",
  "h1": "C:+R"
}

Combines keyword constraints with QPI identifiers.

Condition Patterns

Single Condition

{
  "e4": "empty"
}

A single location constraint.

Multiple Conditions

{
  "a2": "empty",
  "a3": "empty",
  "a4": "enemy"
}

Multiple location constraints in one LCN object.

Multiple Piece Instances

{
  "e1": "S:P",
  "e2": "S:P",
  "e3": "S:P",
  "e5": "S:P",
  "e6": "S:P",
  "e7": "S:P",
  "e8": "S:P",
  "e9": "S:P"
}

Multiple locations constrained to the same piece type.

Common Patterns

Path Specification

{
  "b2": "empty",
  "c3": "empty",
  "d4": "empty"
}

Specifying conditions across multiple locations forming a path.

Target Location

{
  "f5": "enemy"
}

Single target location with enemy constraint (requires active player context for evaluation).

Multi-Location Setup

Castling-style pattern:

{
  "f1": "empty",
  "g1": "empty",
  "h1": "C:+R"
}

En passant-style pattern:

{
  "f6": "empty",
  "f5": "c:-p"
}

Multiple locations with different constraint types.

Game-Specific Patterns

Chess-Style Patterns

Rook path:

{
  "a2": "empty",
  "a3": "empty"
}

Diagonal capture:

{
  "f5": "enemy"
}

Castling conditions:

{
  "f1": "empty",
  "g1": "empty",
  "h1": "C:+R"
}

Shōgi-Style Patterns

Drop location:

{
  "e4": "empty"
}

File pattern:

{
  "e1": "S:P",
  "e2": "S:P",
  "e3": "S:P",
  "e5": "S:P",
  "e6": "S:P",
  "e7": "S:P",
  "e8": "S:P",
  "e9": "S:P"
}

Xiangqi-Style Patterns

Cannon screen:

{
  "b7": "enemy"
}

Palace constraint:

{
  "e1": "C:K",
  "e2": "empty",
  "e3": "c:k"
}

Advanced Patterns with Negation

When used within systems that support negation (like GGN’s deny field), LCN conditions can express additional constraints:

Requiring Allied Pieces

In a system with negation support:

{
  "a1": "enemy"
}

When negated (e.g., in GGN’s deny field), this means: “NOT enemy at a1”, which implies an allied piece must be present (not empty, not enemy = ally).

Requiring Occupied Locations

In a system with negation support:

{
  "b7": "empty"
}

When negated, this means: “NOT empty at b7”, which implies any piece must be present (enemy or ally).

Note: These negation patterns are features of consuming specifications (like GGN), not of LCN itself. LCN only defines the format for positive conditions.

Empty LCN Object

{}

An LCN object with no conditions. Valid format representing the absence of location constraints.

Format Notes

Keys: Must be valid CELL coordinates
Values: Must be either "empty", "enemy", or valid QPI identifiers
Interpretation: How these constraints are evaluated is defined by consuming specifications
Composition: How multiple conditions within one object are combined is defined by consuming specifications
Enemy perspective: The evaluation perspective for "enemy" must be provided by the consuming specification (typically active player)

For semantic interpretation and evaluation rules, consult the specification that uses LCN.