twilightstruggle.app · TSN 2

Twilight Struggle Notation

How to read and write a game of Twilight Struggle in a few characters a round, the way chess players write Nf3 instead of “the knight goes to f3”.

The idea

Chess notation is short because every piece and every square has a fixed code. TSN does the same for Twilight Struggle: every country has a two-letter code, every card a three-character code, and a handful of symbols say how a card was played. A whole action round fits on one line, the USSR's play first and then the US's, as chess writes White's move and then Black's.

1.5   NAS#IR6+3 D3 ; SME=-4

Turn 1, action round 5: the USSR played Nasser for a coup in Iran, rolled a 6 and gained 3 points of influence there, and DEFCON fell to 3; the US played Middle East Scoring, which gave the USSR 4 VP.

A country code is always two letters and a card code always three characters, so one is never mistaken for the other.

A game file

On the board, open the Log tab and press Export (TXT): games against the AI on /ai, and your own games against other players on /play.

A TSN file has three parts, like a chess PGN file.

[Event "Twilight Struggle against the AI"]
[Site "twilightstruggle.app/ai"]
[Date "2026.11.04"]
[US "Player"]
[USSR "AI (Strong)"]
[Result "US wins (DEFCON 1), turn 8, VP 20"]
[Notation "TSN 2"]

1.D   [SEU SME FID KOR COM NAS DGL TRU] ; [FYP SOC BLO MAR CON SUE EEU SPR]
1.S   AT DD HU3 YU ; DK FI FR GR2 NO PA ZA SE
1.H   NAS EG2 ; CON
1.1   CHN/KR3:6 UK5:2 FR2:5 ZA5:5 ; FYP&CR ZA TW DE
...

{seed 1938274651}
{5.15.0.0 5.15.0.0 5.18.0.0 ...}

Tags in square brackets: who played each side, the date, the result.
The game, one line a round, a blank line between turns. Lines starting with # are comments. Once the game is over, each turn opens with the hands as they were dealt (hidden cards).
The replay block in braces, only once the game is over: the seed the cards were dealt from and every decision in the site's own terms. With this site's rules engine it reproduces the game exactly (the site cannot load a file back yet); the game's lines, with their hidden cards, hold the same game without it. Nobody needs to read it, and it is never included while a game is still being played, because it would reveal the hands.

A line

turn.round   USSR's play ; US's play

Round	Meaning
`1.S`	The setup (turn 1 only): the influence each side places.
`4.D`	Turn 4's deal, once the game is over: each side's hand, the USSR's first, cards kept from turn 3 included. See hidden cards.
`4.H`	Turn 4's headline. Both headlines are on one line, the USSR's first, whatever order they resolved in.
`4.1` … `4.8`	Action rounds 1 to 8 of turn 4.
`4.E`	The end of turn 4: what it changed (military operations penalties, DEFCON improving by one). A side that discards a held card with the space race's box 6 does it here.
`—`	No play: an eighth round only one side has (North Sea Oil, the Space Station), or a round the game ended in.

A play

A play is the card's code, then the symbol of how it was played, then what it did.

NAScard #a coup IR6+3where, die, result D3DEFCON now

Symbol	The card was played	Example
`@`	for its event	`COM@PL HU RO DD`
`&`	for its Operations, to place influence	`DGL&FR3`
`#`	for its Operations, for a coup	`NAS#IR6+3`
`/`	for its Operations, for realignment rolls	`TEC/IT4:3 IT2:5`
`*`	on the space race	`IND*1+`
none	as a headline (always its event), or a scoring card	`SOC(CA- IT- UK-)`, `SAS=-1`

An opponent's card played for its Operations

Its event happens too, before or after the Operations, as the player chose. TSN writes both parts in the order they happened, each with what it did.

`IND#PA5+3@(CS2)`	The US played Independent Reds: first a coup in Panama, then the USSR event, which gave the USSR 2 influence in Czechoslovakia.
`NAS@(EG2) &TW`	The US played Nasser: first the USSR event (the USSR gains 2 in Egypt), then the US places 1 influence in Taiwan.
`KOR@xKR4+ #SY6+5`	The US played Korean War: first the war (South Korea, the USSR rolled 4 and won), then a US coup in Syria.

Read the symbols left to right: #…@ is “Operations first, then the event”; @…& is “the event first, then the Operations”. An opponent's card sent to the space race has no event, so it is just *.

Influence

A country's code followed by how much influence changed there. The number is left out when it is one.

`IT`	+1 in Italy
`IT2`	+2 in Italy
`IT-`	−1 in Italy
`IT-2`	−2 in Italy

Whose influence? Outside parentheses: the side that played the card. Inside parentheses: the other side. So in a USSR play, PL2 (FR-2) means the USSR gained 2 in Poland and the US lost 2 in France. In a US play the same text means the US gained 2 in Poland and the USSR lost 2 in France.

This keeps one rule for every event: SUE(FR-2 IL- UK-2) is the USSR's Suez Crisis taking US influence away; COM&AF BX FI@(DD HU PL FI) is the US placing 3 influence with Comecon and then Comecon's event giving the USSR 4.

Dice

A roll is written as the die that came up, not the total: the modifiers follow from the rules and the board.

Written	Meaning
`#IR6+3`	A coup in Iran: die 6, it succeeded and moved 3 points of influence (opponent's removed plus the attacker's added).
`#IR2`	A coup in Iran that failed: die 2, nothing changed.
`/IT4:3`	A realignment roll in Italy: the US die, then the USSR die. Several rolls share one `/`: `/IT4:3 FR2:5`.
`*1+`	A space race attempt: die 1, the marker moved up a box. Without `+` the attempt failed: `*5`.
`xKR5+`	A war card's roll in South Korea (Korean War, Arab-Israeli War, Indo-Pakistani War, Brush War, Iran-Iraq War): die 5, won. Without `+`, lost.
`~3+`	A roll to get out of Quagmire or Bear Trap: die 3, out. Without `+`, still trapped. The card is the one discarded for it.
`d4:6`	The Olympic Games (the sponsor's die, then the other side's) or the Summit (the US die, then the USSR's).

The influence a coup, a realignment or a war changed in its country is told by its die, so that country is not listed again.

Other marks

`>CON`	A card the play brought in: the card Grain Sales took, the card Five Year Plan or Terrorism discarded, the card Star Wars took from the discard pile, the card Missile Envy took.
`=+2` / `=-4`	Victory points the play scored: + for the US, − for the USSR, as on the VP track.
`D3`	DEFCON is now 3.
`{…}`	A comment, as in PGN: `{cancelled by DEF}`. For annotated games, `!`, `?`, `!!`, `??` and comments in braces may follow any play.

Hidden cards

Chess needs only the moves, because both players see the whole board. In Twilight Struggle the plays do not say what each side held: a card kept at the end of a turn is never seen that turn, and the cards Ask Not draws, or Our Man in Tehran shows and puts back, are seen only by the US. So once a game is over, TSN writes them too, between square brackets: hidden information, made public. A file exported while the game is still being played leaves them out.

`5.D [FYP … ASK] ; [SOC … CB5]`	Turn 5's deal: each side's hand once the turn is dealt, the USSR's first, before the headline (on turn 1, before the setup). The cards a side kept from turn 4 are the ones in its hand that turn 4's line did not deal it. The China Card is not listed: whose it is follows from the plays.
`[JUN PEC]`	After a play, the cards it drew from the deck into the hand of the side that played. `([JUN PEC])`: into the other side's hand.
`[^NTB KIT]`	Cards the side that played saw and put back on the deck (Our Man in Tehran). `([^NTB KIT])`: the other side saw them.

5.2   ASK#MY1@ >WWB >PAN >SOC >ALL >CB5 ([JUN PEC PUP GRA LIB]) ; JUN#VN4+4

The USSR played Ask Not What Your Country Can Do For You, a US card, for a coup in Malaysia: die 1, it failed.
Then its US event: the US discarded five cards, which both sides saw (>WWB >PAN >SOC >ALL >CB5), and drew five from the deck, which only the US saw: in brackets, and in parentheses because they went into the other side's hand.
The US then played one of them, Junta, for a coup in Vietnam.

Ask Not is the only card that draws from the deck in the middle of a turn. Cards that move from a hand or the discard pile in front of both players (Grain Sales, Missile Envy, SALT Negotiations, Star Wars, Five Year Plan, Terrorism) are public and written with >. With the deals, the cards drawn and the plays, a file holds the whole game.

5.4   OMT&CS SE@ >SAL ([^NTB KIT OPE SAD]) ; SAU*2+

The USSR played Our Man in Tehran, a US card, for influence in Czechoslovakia and Sweden; then its US event.
The US drew the top five cards of the deck and discarded SALT Negotiations, in front of both sides (>SAL).
It put the other four back on the deck, which is then shuffled: only the US saw them, so they are in brackets, with ^ for “back on the deck”, and in parentheses because the US is the other side here. They do not change the game, as the deck is shuffled; they say what the US knew.

Worked examples

4.2   CRG@(AO BU MA VN) /IB2:5 WA3:3 ; SPR@CA

4.2: turn 4, action round 2.
CRG: the USSR played Colonial Rear Guards, a US card worth 2 Operations.
@(AO BU MA VN): its US event came first and gave the US (the other side, so in parentheses) 1 influence each in Angola, Burma, Morocco and Vietnam.
/IB2:5 WA3:3: then the USSR used the 2 Operations for two realignment rolls: in Spain/Portugal the US rolled 2 and the USSR 5; in the West African States both rolled 3.
; SPR@CA: the US played Special Relationship for its event and gained 1 in Canada.

1.H   SPR(CA) ; CON

The USSR's headline was Special Relationship, a US card: its event gave the US 1 in Canada, so it is in parentheses.
The US headline was Containment.

2.3   EEU&LY TW@DD- PL- ; IPW#PA2 D3

The USSR played East European Unrest, a US card: first its Operations for influence in Libya and Taiwan, then the US event, which cost the USSR 1 in East Germany and 1 in Poland (the USSR's own influence, so no parentheses).
The US played Indo-Pakistani War for a coup in Panama, rolled 2 and failed; DEFCON fell to 3.

1.6   FYP&AF2 IT >CON ; WPF&FR MA PA@(DD2 HU2 RO)

The USSR played Five Year Plan, a US card, for influence: 2 in Afghanistan, 1 in Italy. Its event then discarded Containment from the USSR's hand at random.
The US played Warsaw Pact Formed, a USSR card, for influence in France, Morocco and Panama; then its event gave the USSR 2 in East Germany, 2 in Hungary and 1 in Romania.

8.7   ORT@#CU1 D1 ; —

The USSR played Ortega Elected in Nicaragua for its event and its free coup in Cuba, rolled 1, and DEFCON fell to 1: nuclear war. The game ended; the US had no play left in that round.

Writing by hand

Start the line with the turn and the round: 3.4.
Write the USSR's play, a space, ;, a space, the US's play.
For each play: the card's code, then @ & # / * in the order things happened.
After each symbol, what it did: the countries where the player's influence changed, then the other side's in parentheses; the dice after their own symbol.
End with > for any card brought in, = for VP, D for DEFCON.
Once the game is over, open each turn with its deal, 3.D [USSR's hand] ; [US's hand], and write the cards Ask Not drew in brackets after its play, and the ones Our Man in Tehran put back as [^…].
Leave the count out when it is 1, and leave out what the rules make of the play.

What is not written

As chess does not write that a bishop moved diagonally, TSN leaves out what follows from the rules: military operations, effects in play (NATO, Containment, Quagmire…), modifiers to dice, the space race's box after a success, and a card's choice when it changed nothing on the board. The rules give it back from the board, and the replay block settles anything a reader is unsure of.

Country codes

The country's ISO 3166 code where it has one, including the historical codes of countries that no longer exist (DD East Germany, CS Czechoslovakia, YU Yugoslavia, BU Burma, ZR Zaire). UK is used for the United Kingdom, as ISO reserves it. The board's groups of countries have their own codes: BX Benelux, IB Spain/Portugal, GS Gulf States, WA West African States, SS Saharan States, SF SE African States.

Regions

Only after a card that names a region (Chernobyl, a scoring card): a capital and a small letter, so they never look like a country. Eu Europe, As Asia, Me Middle East, Af Africa, Ca Central America, Sa South America, Se Southeast Asia. Example: CNB@As.

Card codes

Three characters, mostly the first letters of the name; scoring cards are S and their region (SEU Europe Scoring). The number is the card's number in the game.