PMN Examples

Learn Portable Move Notation (PMN) through progressive examples, from basic moves to multi-action moves (captures, drops, special moves).

PMN encodes Moves (ordered sequences of protocol-level Actions). Many moves are 1 Action, but some PMN forms imply 2 Actions (e.g., capture-moves and capture-drops).

Quick reference

Forms (operators and shapes)

Form	Example	Meaning	Direct effect (Actions)
Pass	`...`	Pass move	0
Move (quiet)	`e2-e4`	Move to empty square	1
Move (capture)	`d1+f3`	Capture at destination then move actor	2
Static capture	`+d4`	Capture a piece on a square (no actor move)	1
Special move	`e1~g1`	Move with rule-defined implicit effects	≥ 1
Drop (quiet)	`Pe5` or `e5`	Drop from hand to empty square	1
Drop (capture)	`L.b4` or `.b4`	Capture at destination then drop actor	2
In-place mutation	`e4=+P`	Mutate piece already on a square	1

Notes:

+ has two forms: infix (src+dst) and prefix (+square).
= is both an operator (square=piece) and a suffix (...=piece) depending on context.

Suffixes (transformations)

Suffixes encode Mutations. They are governed by a strict rule: a suffix MUST appear if and only if the corresponding Piece Identity changes. Presence signals a mutation; absence signals none. A suffix that encodes an unchanged identity is non-conforming and must be rejected.

Suffix	Example	Applies to	Meaning
`=<piece>`	`e7-e8=Q`	Actor	The actor’s Piece Identity changes — encode the post-mutation EPIN
`/<piece>`	`d4+e5/S`	Captured piece	The captured piece’s Piece Identity changes — encode the post-mutation EPIN

Ordering (when both are present): actor transformation first (=), capture transformation second (/).

Basic moves

Simple move (`-`)

e2-e4

Meaning: the piece at e2 moves to the empty square e4. No mutation occurs, so no suffix.

Direct effect:

1 Action: Board(e2) → Board(e4)

Capture-move (`src+dst`)

d1+f3

Meaning: capture the piece on f3, then move the actor from d1 to f3. In a standard Chess capture, the captured piece enters the Active Player’s Hand with its identity unchanged — no mutation, so no suffix.

Direct effect:

2 Actions:
1. Board(f3) → Active Player’s Hand
2. Board(d1) → Board(f3)

Transformations (EPIN)

Actor transformation (`=<piece>`)

The =<piece> suffix encodes a mutation of the actor’s Piece Identity. It is present when, and only when, that identity changes as a result of the move.

e7-e8=Q

Meaning: the pawn moves from e7 to e8 and promotes to a Queen (P → Q). The suffix =Q encodes that mutation.

Direct effect:

1 Action: Board(e7) → Board(e8) with actor mutation to Q

A move to a non-promoting square — say e7-e6 — would carry no suffix, because the pawn’s identity is unchanged.

Capture transformation (`/<piece>`)

The /<piece> suffix encodes a mutation of the captured piece’s Piece Identity. It is present when, and only when, that identity changes upon capture.

d4+e5/S

Meaning: the piece at d4 captures on e5. The captured promoted piece (+S) reverts to its base form (S) upon capture — a mutation occurs, so the suffix /S is present and encodes the post-mutation EPIN.

Direct effect:

2 Actions:
1. Board(e5) → Active Player’s Hand with captured mutation to S
2. Board(d4) → Board(e5)

This pattern is common in Ōgi-like rule systems where captured promoted pieces are automatically demoted.

When the captured piece enters the hand unchanged — as in a standard Chess capture — the suffix is absent entirely. d4+e5 is the correct form for a capture with no mutation.

Side change on capture

d4+e5/s

Meaning: the piece at d4 captures on e5. The captured piece changes side (e.g., S becomes s) — a mutation occurs, so /s is present.

Direct effect:

2 Actions:
1. Board(e5) → Active Player’s Hand with captured mutation to s
2. Board(d4) → Board(e5)

Combined transformations

b7+a8=Q/r

Meaning: a pawn at b7 captures on a8. The actor promotes to Q (actor mutation), and the captured piece changes from R to r (captured mutation). Both mutations occur, so both suffixes are present.

Direct effect:

2 Actions (capture first, then actor move), with both mutations applied to their respective Actions.

Static capture (`+square`)

Capture without moving an actor

+d4

Meaning: capture the piece located on d4 (useful for custodial captures, ranged effects, or rule-driven removals). The captured piece enters the Active Player’s Hand with its identity unchanged — no suffix.

Direct effect:

1 Action: Board(d4) → Active Player’s Hand

With capture transformation

+d4/p

Meaning: same capture, but the captured piece’s Piece Identity changes — it enters the hand as p. The mutation is encoded as /p.

Direct effect:

1 Action: Board(d4) → Active Player’s Hand with captured mutation to p

Special moves (`~`)

Castling-like example

e1~g1

Meaning: the actor moves from e1 to g1. The ~ signals that the Rule System may add implicit effects (e.g., moving a rook). The actor is unchanged, so no =<piece> suffix.

Direct effect:

≥ 1 Action: Board(e1) → Board(g1)

Implicit effects (rule-defined):

May include additional Actions (e.g., rook displacement).

En passant-like example

e5~f6/p

Meaning: the actor moves from e5 to f6. An implicit capture occurs (en passant), and the captured piece changes side in the process (e.g., P → p). The mutation is encoded as /p.

Direct effect:

≥ 1 Action: Board(e5) → Board(f6), plus implicit capture by Rule System.

The /<piece> suffix is present here because two conditions are simultaneously true: a capture occurs, and the captured piece’s identity changes. If the captured piece had entered the hand unchanged, the suffix would be absent. If no capture occurred at all, the suffix would equally be absent.

Drops

Drop to empty square (`*`)

P*e5

Meaning: drop a pawn from the Active Player’s Hand onto e5. No mutation occurs on drop, so no suffix.

Direct effect:

1 Action: Active Player’s Hand → Board(e5)

Drop with actor mutation

S*c3=+S

Meaning: drop piece S from the Active Player’s Hand onto c3. Upon landing, the piece is promoted (S → +S). The mutation is encoded as =+S.

Direct effect:

1 Action: Active Player’s Hand → Board(c3) with actor mutation to +S

Contextual drop (piece omitted)

*e5

Meaning: drop some piece from the Active Player’s Hand onto e5.

Guideline: omitting the piece identifier is only appropriate if the Rule System (or surrounding context) can uniquely determine which hand-piece is being dropped.

Drop with capture (`.`)

L.b4

Meaning: capture the piece on b4, then drop L onto b4. The captured piece enters the Active Player’s Hand with its identity unchanged — no suffix.

Direct effect:

2 Actions:
1. Board(b4) → Active Player’s Hand
2. Active Player’s Hand → Board(b4) (dropping L)

In-place mutation (`square=piece`)

e4=+P

Meaning: mutate the piece currently on e4 into +P without moving it. The target EPIN must differ from the current one — a no-op in-place mutation is non-conforming.

Direct effect:

1 Action: mutation-only on Board(e4)

Game sequence example

A Chess opening (Italian Game), expressed as PMN moves:

e2-e4
e7-e5
g1-f3
b8-c6
f1-c4
f8-c5

Each line is one Move (1 Action here), alternating between sides. None of these moves involve mutations, so no transformation suffixes appear.

PMN Examples

Quick reference

Forms (operators and shapes)

Suffixes (transformations)

Basic moves

Simple move (-)

Capture-move (src+dst)

Transformations (EPIN)

Actor transformation (=<piece>)

Capture transformation (/<piece>)

Side change on capture

Combined transformations

Static capture (+square)

Capture without moving an actor

With capture transformation

Special moves (~)

Castling-like example

En passant-like example

Drops

Drop to empty square (*)

Drop with actor mutation

Contextual drop (piece omitted)

Drop with capture (.)

In-place mutation (square=piece)

Game sequence example

Simple move (`-`)

Capture-move (`src+dst`)

Actor transformation (`=<piece>`)

Capture transformation (`/<piece>`)

Static capture (`+square`)

Special moves (`~`)

Drop to empty square (`*`)

Drop with capture (`.`)

In-place mutation (`square=piece`)