Fire in the Lake: Tru'ng Bot Update Pack Rulebook

Table of Contents

Table of Contents

• T1. Introduction & Components
  • T1.1 Overview
  • T1.2 Trưng Rules Notation
  • T1.3 Components
• T2. Golden Rules
  • T2.1 Golden Rules
• Important Trưng Terms
• T3. Victory
  • T3.1 Playing Solitaire
  • T3.2 Playing With Two or Three Players
• T4. Setup
  • T4.1 Setting Up NP Factions
• T5. Sequence of Play
  • T5.1 Overview
  • T5.2 NP Sequence of Play
  • T5.3 Executing Operations and Special Activities With Trưng Cards
  • T5.4 Activation Numbers
  • T5.5 Executing Events
  • T5.6 Space Selection Priorities Tables
  • T5.7 Move Priorities Table
  • T5.8 Piece Priorities Table
  • T5.9 Coup Rounds
• Capabilities Instructions

T1. Introduction & Components

T1.1 Overview

Trưng is an updated Non-player (NP) system, replacing the system included in the Fire in the Lake base game. A deck of cards and several player aid tables replace the flowcharts of the original Non-player Factions. Trưng is named in honor of Trưng Trắc and Trưng Nhị, two sisters who briefly freed Vietnam from Chinese occupation in the 1st century CE. This rulebook explains how to use the provided cards and charts to play Fire in the Lake against NP opponents.

A detailed reference, with step-by-step procedures and several examples of play, is provided in the Reference Booklet (sections T6.0 through T9.0). [Gap: the Reference Booklet is not included in this transcription. See the note in the Table of Contents.]

T1.2 Trưng Rules Notation

All Trưng rules are preceded by a T.

T1.3 Components

T1.3.1 Trưng Cards. Each NP Faction has six Trưng cards that provide instructions for selecting and executing Operations and Special Activities.

T1.3.2 Priorities Tables. Trưng includes three types of Priorities tables: Space Selection, Move, and Pieces. Each Faction uses its own Space Selection Priorities table. All Factions share the Move Priorities and Pieces Priorities tables.

T1.3.3 NP Eligibility Table. The NP Eligibility table determines how an Eligible NP Faction will act on the Current Event card.

T1.3.4 Event Tables. There are four Events tables: Event Card, Effective Events, Event Instructions, and Capability Effects.

T1.3.5 Coup Round Instructions. The Coup Round instructions guide the actions of each NP Faction during Coup Rounds.

T2. Golden Rules

T2.1 Golden Rules

T2.1.1 NP Factions Follow the Rules (Almost). NP Factions abide by all Fire in the Lake rules, with these exceptions:

• NP Factions never remove pieces from the map to Available when lacking pieces for an Operation, Special Activity, or Event (EXCEPTION: NP US Train with Combined Action Platoons).
• NP NVA and NP VC do not track Resources.
• NP US and NP ARVN do not track Resources when both are NP Factions. NP US or NP ARVN only track ARVN Resources when the other COIN Faction is a player Faction (T5.4.3). Ignore any instructions to increase or decrease NP Resources when they are not tracked. Transfers to NP ARVN Resources by NP US due to US Train still reduce Patronage, but add no ARVN Resources.
• NP Factions roll against an Activation Number to limit total spaces selected (T5.4).
• NP NVA may March when the Trail is 4 as though spaces in and adjacent to Laos and Cambodia are adjacent to each other (T6.3.2).

T2.1.2 Skip Illegal Instructions. Trưng will only tell you what to do, it will not tell you how to do it or even if its instructions constitute a legal move given the state of the board and available pieces. Always carry out Trưng's instructions as much as possible, but if Trưng ever gives you an instruction that cannot be carried out legally, just skip it.

T2.1.3 Placing Friendly Pieces. When executing Operations, Special Activities, or Events that allow the acting Faction to place several pieces in multiple spaces, NP Factions place pieces one at a time, placing their own pieces before any other Factions, if possible. In such cases, select the destination for each piece one at a time, using the NP Faction's Space Selection Priorities table. During Train and Rally Operations, NP Factions will place as many pieces as possible, following the directions on the Trưng card. If multiple types of pieces could be placed, determine the piece to be placed using the Piece Priorities Table.

T2.1.4 Removing Friendly Pieces. When given a choice, NP Factions remove pieces one at a time from the space with the most pieces belonging to the affected NP Faction. Use the Piece Priorities table to select pieces to remove from each selected space.

T2.1.5 Events, Ops & SA to the Maximum Extent. NP Factions always execute a selected Event, Operation or Special Activity to the maximum extent allowed, given the state of the board, available pieces, and Activation Number die rolls.

T2.1.6 When in Doubt, Randomize. Whenever NP Factions need to select from among several options and supplied instructions have been exhausted, select one option at random.

Important Trưng Terms

1d6, 2d6, 3d6, 1d3. Die or dice roll to generate a random number. 1d6 means roll the die once; 2d6 means sum two dice, etc. 1d3 means roll one die and halve the result, rounding up.

Activation Number. A limit on the total number of spaces selected by NP Factions for most Operations. When present, the active NP Faction must roll greater than its Activation Number to select another space (T5.4).

Agitate Total. A measure of NP VC Agitate capabilities, increased during the NP VC Tax Special Activity and spent during NP VC Agitate during the Support Phase of each Coup Round (and during NP VC Rally if the shaded Cadres Capability is in effect).

ARVN Firepower. The maximum number of enemy pieces that could be removed during an ARVN Assault in a given space, including any modifications due to terrain, force composition, Capabilities, and/or Momentum effects, independent of whether any enemies are present.

Blocked LoC Route (from Can Tho to Hue). A blocked LoC route is any continuous chain of adjacent LoCs and Cities where any LoC or City in the chain has enemy pieces.

COIN Firepower. The maximum number of enemy pieces that could be removed during a US Assault in a given space, including any modifications due to terrain, force composition, Capabilities, and/or Momentum effects, and including the participation of any ARVN forces present, independent of whether any enemies are present.

Effective Event. An Event is Effective if one or more of its effects are listed for the acting NP Faction on the Effective Events table (T5.5.1).

Get. Move just enough pieces to the destination to meet the instruction, taking into account any pieces already present in the space. If no additional pieces are needed to meet the instruction, move none. If there are insufficient pieces to meet the instruction, move as many as possible.

Keep. Leave just enough pieces in the origin to meet the instruction. If there are insufficient pieces to meet a particular instruction, ignore it.

Most/Least Support/Opposition. Among all spaces with Support, spaces with the most Support are those with the most total Support (1.6). Spaces with the least Support are those with no Support first (Neutral and Opposition spaces), then spaces with the least total Support. Among all spaces with Opposition, spaces with the most Opposition are those with the most total Opposition (1.6). Spaces with the least Opposition are those with no Opposition first (Neutral and Support spaces), then spaces with the least total Opposition.

NP. Non-player.

US Policy. If the US is an NP Faction, it will follow a varying strategy, represented by 'JFK', 'LBJ', or 'Nixon' US Policy and tracked by the US Policy box on the game board, in its execution of certain Operations, Special Activities, Events, and Commitment.

Vulnerable Bases. NVA and VC Bases in spaces without Underground Guerrillas.

Vulnerable Enemies. From a COIN Faction perspective: NVA Troops, Active NVA and VC Guerrillas, and NVA and VC Bases in spaces without Underground Guerrillas.

Within Reach. A space is within reach of moving pieces if those pieces could move to that space during the selected Operation or Special Activity (including via LoCs or Laos/Cambodia).

T3. Victory

T3.1 Playing Solitaire

When playing solitaire against Trưng, the player may only win during the final Coup Round. NP Factions may win during the Victory Phase of any Coup Round, or following the Redeploy Phase of the final Coup Round.

T3.2 Playing With Two or Three Players

When playing with multiple players, any Faction may win during any Coup Round.

T4. Setup

T4.1 Setting Up NP Factions

T4.1.1 Select Scenario. Select a scenario to play. Trưng fully supports any scenario, however for more of a challenge, we recommend playing the Medium or Full scenarios.

T4.1.2 Select NP Factions. Any combination of player and NP Factions may be used. For each NP Faction, collect its six matching Trưng cards.

T4.1.3 Create the Trưng Deck. Shuffle all the cards for all NP Factions into one deck, face up.

T4.1.4 Resource Cylinders. NP NVA never uses its Resource cylinder; set it aside. Set the NP VC Resource cylinder to 1d3 as its starting Agitate Total. If both the US and ARVN are NP Factions, set aside the ARVN Resource cylinder and Econ marker. If either the US or ARVN is a player Faction, set up the ARVN Resource cylinder and Econ and Aid markers according to the instructions for the chosen scenario.

T4.1.5 NP US Policy. If the US is an NP Faction, set up its Policy marker according to the scenario instructions.

T4.1.6 Finishing Setup. Set up the rest of the scenario normally per the scenario instructions.

T5. Sequence of Play

T5.1 Overview

Generally, NP Factions make the same decisions as player Factions. First, Eligible NP Factions determine if and how they will act on the current Event card. The Trưng card deck is used to select Operations and Special Activities and provide instructions to execute that action. Event tables guide an NP Faction's selection and execution of Events. Priorities tables are used to select spaces where NP Factions will act, how NP Factions move pieces, and which friendly and enemy pieces are affected by an action.

T5.2 NP Sequence of Play

NP Factions follow the base game Sequence of Play and Eligible NP Factions choose from the same options as player Factions. Use the Eligibility table (T1.3.3) and Event Card table (T5.5.1) to determine the choice made by an Eligible NP Faction. If the NP Faction selects an Operation plus Special Activity, Operation only, or Limited Operation, use the active NP Faction's Trưng cards and the various Priorities tables to select and execute the Operation and any Special Activity. If the NP Faction selects an Event, execute the Event using the various Event and Priorities tables. If the NP Faction selects Pass, there is no additional effect (EXCEPTION: NP COIN Passing when the other COIN Faction is a player Faction adds +3 ARVN Resources).

T5.3 Executing Operations and Special Activities With Trưng Cards

Each NP Faction has six Trưng cards that provide instructions for selecting and executing Operations and Special Activities.

[Figure: the Trưng card anatomy diagram. Its callouts, from the printed figure, are: Faction & Card ID; Activation Number; Condition; Draw New Card; Operation; Flip Card; Special Activity; Stop. The figure itself is not reproduced.]

T5.3.1 Face Up and Face Down. Face up sides are identified by a single letter and face down sides by a double letter. Except when acting as the active card, cards in the Trưng deck should be face up.

T5.3.2 Setting Up the Trưng Deck. At the start of the game and during the Reset Round of each Coup Phase, shuffle together face up all Trưng cards for all NP Factions into a single deck.

T5.3.3 Drawing Trưng Cards. First, move the top card to the bottom of the deck (even if this top card matches the active NP Faction). Continue moving cards to the bottom, one at a time, until a card matching the active NP Faction is the top card. Always place cards on the bottom of the deck face up.

T5.3.4 Reading Trưng Cards. Start at the top of the card with the first blue box. If the condition in the box is true, follow the green arrow; if it is false, follow the red arrow.

T5.3.5 Drawing a New Card and Flipping a Card. If an arrow points to the draw icon, draw a new card. If an arrow points to the flip icon, flip the card to its face down side.

T5.3.6 Executing Operations. Execute each numbered instruction in order, as much as possible. Follow the instructions on the Trưng card to select spaces, using the active NP Faction's Space Selection priorities table when directed. Text in bold specifies the column of that NP Faction's Space Selection Priorities table to use. Starred instructions are executed last.

Instructions that follow a red conditional are only executed if that condition is true. If there are no legal spaces for the selected Operation, draw a new Trưng card to select a different Operation. See T6. Operations Reference for detailed instructions of each Operation.

T5.3.7 Executing Special Activities. Execute one Special Activity from the list, in letter order. Underlined text specifies the Special Activity. Within each Special Activity, execute each numbered instruction in order, as much as possible. Text in bold specifies the column of that NP Faction's Space Selection Priorities table to use when selecting spaces if multiple spaces could be selected within the instructions given on the card. If a Special Activity cannot be executed, or its red condition is not true, skip it and execute the next one. If no Special Activity can be executed, select Operation only instead (2.3.4). See T7. Special Activities Reference for detailed instructions of each Special Activity.

T5.3.8 Monsoon, Loops, and Edge Cases. During a Monsoon, before executing any Special Activity for an NP Faction, check that the accompanying Operation can be performed; if it cannot, draw a new Trưng card to select a different Operation and Special Activity. In rare cases, a Special Activity may be performed that would preclude a legal Operation; in this case, skip that Operation and end the NP Faction's turn after placing their eligibility cylinder in the Operation and Special Activity box in the Sequence of Play. If at any time, all Trưng cards for a given Faction are drawn without finding a legal Operation for the NP Faction to perform, continue to the next line of the NP Eligibility Table (T1.3.3).

T5.4 Activation Numbers

The total number of spaces that NP Factions select for Operations are limited by an Activation Number. Activation Numbers are found on the upper right of most Trưng cards and indicated by a die icon; that number is used for all Operations on that side of the card. Some Operations (all NP US except for Train Operations that place ARVN cubes and NP ARVN Patrol) do not use an Activation Number and thus are not limited by the Activation Number roll. Other Operations (NP NVA and NP VC March and NP VC Terror) do not trigger Activation Number rolls when executed on LoCs. Limited Operations do not trigger Activation Number rolls as they are performed in only one space.

T5.4.1 Checking the Activation Number. After executing the Operation in a selected space, roll 1d6. If the result is less than or equal to the Activation Number, the NP Faction will not select any additional spaces; implement any starred Operations instructions. If the result is greater than the Activation Number, the NP Faction will select another space for Operations. Continue rolling as above after executing the Operation in each selected space until the Activation Number roll is less than or equal to the Activation Number or no eligible spaces remain for the Operation.

T5.4.2 Activation Number Exceptions. NP ARVN does not make an Activation Number roll during Patrol Operations. NP NVA and NP VC do not make an Activation Number roll after Marching onto a LoC; select another March destination without rolling. NP VC does not make an Activation Number roll after executing Terror on a LoC. The Activation Number for NP NVA is 1 during March Operations when the Trail is 4. Note that NP ARVN during Train will attempt to place a Base, and NP NVA during Rally will improve the Trail, even after failing the Activation Number roll.

T5.4.3 Resources. NP NVA and NP VC do not track or spend Resources. NP US and NP ARVN only spend ARVN Resources when the other COIN Faction is a player Faction. When one COIN Faction is an NP Faction and the other COIN Faction is a player Faction, the NP Faction will make Activation Number rolls as normal, but will not execute an Operation or Pacify once there are insufficient Resources to pay for that action (just like a player Faction).

T5.5 Executing Events

T5.5.1 Event Tables. There are four Event tables: Event Card, Effective Events, Event Instructions, and Capability Effects. The Event Card table lists whether each Event is Critical, Performed, or not executed for each NP Faction. The Effective Events table lists the types of Event actions that are Effective. When given a choice, NP Factions only execute actions that are Effective. The Event Instructions table gives specific instructions for executing certain Events. The Capabilities Effects table on the back of this booklet specifies any additional instructions for any Capabilities that are in play.

T5.5.2 Events Executed by 1st and 2nd Eligible NP Factions. A 1st Eligible NP Faction will execute an Event if it is marked Critical for that NP Faction on the Event Card table and, if executed, would result in one or more of the effects listed for that NP Faction on the Effective Events table. A 2nd Eligible NP Faction will execute an Event if it is marked either Critical or Performed for that NP Faction on the Event Card table and, if executed, would result in one or more of the effects listed for that NP Faction on the Effective Events table. Neither 1st nor 2nd Eligible NP Factions will execute Events marked NP Does not Execute for the active NP Faction on the Event Card table.

T5.5.3 Event Instructions. Some Events require additional instructions to guide NP Faction play. These Events are marked ★C or ★P on the Event Card table. If multiple spaces can be selected within the instructions provided, select from among remaining spaces per T5.5.6.

T5.5.4 Unshaded or Shaded? NP US always selects unshaded Event text and NP VC always select shaded Event text. NP ARVN generally selects unshaded Event text, unless executing an Event marked C on the Event Card table. NP NVA generally selects shaded Event text, unless executing the Event marked P on the Event Card table. For Events that are not Dual Use, all NP Factions use the unshaded text.

T5.5.5 Place Friendly, Remove Enemy. When given a choice, NP Factions only place friendly pieces and only remove enemy pieces.

T5.5.6 Selecting Spaces. Select spaces using the column of the active NP Faction's Space Selection Priorities that matches the Effective Event action. If the Event performs more than one Effective action in a single space, use the leftmost matching column.

T5.5.7 Events That Allow Operations or Special Activities. Draw a Trưng card for the active NP Faction to select an Operation or Special Activity. If the Event specifies the Operation or Special Activity, draw Trưng cards until a matching Operation or Special Activity is drawn (check both sides).

T5.5.8 Pivotal Events. NP Factions play their Pivotal Event when the red precondition for the Event has been met, that NP Faction is Eligible, the current Event is not Critical for that NP Faction, and a 1d6 roll is less than the number of cards in the RVN Leader box.

T5.5.9 Faction-Specific Reference. See T8. Events Reference for NP Faction-specific guidelines.

T5.6 Space Selection Priorities Tables

There are four Space Selection Priorities tables, one for each NP Faction. Use an NP Faction's Space Selection Priorities table to select spaces for Operations, Special Activities, Events, and during Coup Rounds. First, determine the type of action the NP Faction will execute to determine the column to use on the Space Selection Priorities table. During Operations and Special Activities, use the column specified by the bold text on the Trưng card. During Events, use the column that matches the Effective action specified in the Event text. If an Event performs more than one Effective action in a single space, use the leftmost matching column on the Space Selection Priorities table. During Coup Rounds, follow the instructions on the Coup Round instructions sheet.

[Figure: the NP Republic of Vietnam Space Selection Priorities (T5.6) table, a grid of dots by row condition and column action (Shift Toward Passive Support, Place Bases, Place Cubes or Rangers, Sweep or Transport Destinations, Patrol Destinations, Govern, Remove or Replace). The dot grid is an image and is not transcribed here; consult the printed page 6 of the rulebook or the NP player aid.]

T5.6.1 Selecting a Space. When executing an Operation, Special Activity, or Event select each space one at a time:

• Step 1. Start at the top of the column and read down. For each row with a dot in that column, check its condition against all spaces which could be selected. Some rows contain conditional statements, marked by a red checkmark, that must be true for any dot to apply. If no spaces meet the condition, skip that row and continue to the next. If only one space meets this condition, execute the Operation, Special Activity, or Event in this space. Otherwise:
• Step 2. If more than one space meets this condition, continue down the column to the next condition that is met. Continue to skip conditions that are not met or whose red conditional statement is not true. If only one space meets both the original condition and the new condition, execute the action in this space (as in Step 1).
• Step 3. Continue this process, checking each row below and applying all meeting conditions, until a single space is selected.
• Step 4. Repeat this process from Step 1 for each space to be selected.

T5.6.2 Random Spaces. To select a space at random, assign equal probability to each candidate space and roll a die. In the event that an NP Faction needs to select at random from among many spaces, use the Random Spaces chart that accompanied the base game.

T5.7 Move Priorities Table

Whenever an NP Faction needs to move its pieces on the map, use the Move Priorities table. Read down the column that matches the active NP Faction, executing each instruction in a dotted row. Dotted rows with a red conditional only match if the condition is true. See T6. Operations Reference and T7. Special Activities Reference for detailed instructions of Operations and Special Activities that move pieces.

T5.7.1 Step A. Select a destination space using the instructions on the Trưng card, and if none, use the column of the active NP Faction's Space Selection Priorities table that matches the selected Operation or Special Activity.

T5.7.2 Step B. Select an origin space: choose the space with the most movable pieces that is within reach of the destination and that has not already been selected as a destination during this Operation or Special Activity. A piece is movable if it may be moved by the selected Operation or Special Activity. The starred instruction applies only when the Trail is 4, and allows NP NVA to March between any spaces in and adjacent to Laos and Cambodia as though they were adjacent to each other.

T5.7.3 Keep Pieces. Reading down the column that matches the active NP Faction, keep pieces in the selected origin as instructed by each dotted row. Instructions that follow a red conditional are only executed if that condition is true.

T5.7.4 Move Pieces. Reading down the column that matches the active NP Faction, move pieces into the selected destination as instructed by each dotted row. Instructions that follow a red conditional are only executed if that condition is true.

T5.7.5 Steps C & D. After all moving pieces have moved from the first origin, check to see if additional origins or destinations will be selected. To select a new destination, return to Step A. To select a new origin, return to Step B. Note that the NP Faction may need to pass an Activation Number roll to select additional destination spaces during Operations (T5.4).

T5.7.6 No-Op Movement. If a space is selected as a destination for movement, but no pieces are able to move to that space due to instructions in the Move Priorities table, eliminate that space as a potential destination for that action. It is not considered to have been selected as a destination and may be selected as an origin space for a different destination during that action.

[Gap: the Move Priorities table itself is not printed in this rulebook file. It is a separate player aid; the dotted-row instructions it contains are not transcribed here.]

T5.8 Piece Priorities Table

When an NP Faction needs to select pieces from among several different types, use the Piece Priorities table. When placing friendly pieces or removing, replacing, or Activating enemy pieces, start from the top and read down; within boxes, read left to right. When removing friendly pieces, start from the bottom and read up; within boxes, read right to left.

[Gap: the Piece Priorities table itself is not printed in this rulebook file; it is a separate player aid and is not transcribed here.]

T5.9 Coup Rounds

Follow the instructions on the Coup Round instructions sheet for all NP Factions. Use the NP Coup Round instructions sheet whenever any NP Faction would need to make a decision during a Coup Round.

[Gap: the NP Coup Round instructions sheet is a separate player aid and is not included in this transcription.]

The printed rulebook closes this section with: "You know enough to play Fire in the Lake using Trưng. The included Reference Booklet contains several examples of play that you can set up and follow along with to help you learn to play."

[Gap: the Reference Booklet (sections T6.0 through T9.0), including the Operations Reference (T6), Special Activities Reference (T7), Events Reference (T8), and examples of play, is not included in this transcription.]

Capabilities Instructions

The printed rulebook lists these under "Capabilities Instructions" in its table of contents (page 8), on the back of the booklet.

US Unshaded Capability Instructions:

• Abrams: Use the Remove or Replace column of the Space Selection Priorities table to select among eligible Assault spaces.
• Arc Light: Use the Remove or Replace column of the Space Selection Priorities table to select among eligible Air Strike spaces.
• Cobras: Use the Remove or Replace column of the Space Selection Priorities table to select among Sweep destinations.
• Combined Action Platoons: Get ARVN Police into a space without Support, no Police, and most Population.
• CORDS: Use the Shift Toward Support column of the Space Selection Priorities table to select among eligible spaces.
• Laser Guided Bombs: Remove only one enemy piece per selected Air Strike space, unless that space is at Active Opposition.
• M-48 Patton: Use the Remove or Replace column of the Space Selection Priorities table to select among eligible Lowland Assault spaces. Unshaded M-48 does not affect US Firepower calculations.
• Search and Destroy: Remove VC before NVA.
• SA-2s: Uses the Remove or Replace column of the US Space Selection Priorities table to select an eligible space: with NVA Bases first, then NVA Troops, then NVA Guerrillas.

US Shaded Capability Instructions:

• Arc Light: Remove only one enemy piece per selected Air Strike space, unless that space is at Passive or Active Opposition.
• Booby Traps (VC): Select up to two spaces for Sweep.
• Cobras: Select up to two spaces for Assault.
• M-48 Patton: NP US will not execute Patrol Operations. Draw a new Trưng card to select another Operation.
• Search and Destroy: Assault only where NVA Troops or vulnerable enemy Base.

ARVN Unshaded Capabilities:

• Armored Cavalry: Use the Remove or Replace column of the Space Selection Priorities table to select eligible Assault space from among Transport destinations.
• Cobras (US): Use the Remove or Replace column of the Space Selection Priorities table to select among Sweep destinations.
• Mandate of Heaven: Select the space with least Support.

ARVN Shaded Capabilities:

• Booby Traps (VC): Select up to two spaces for Sweep.

NVA Shaded Capabilities:

• PT-76: Use in the space with the most NVA Troops.

NVA Unshaded Capabilities:

• AAA: NP NVA will only improve the Trail if it is 0 - 2.
• MiGs: No effect (NP NVA does not use Resources, T5.4.3).
• SA-2s: NP US uses the Remove or Replace column of the US Space Selection Priorities table (8.4.1) to select an eligible space: with NVA Bases first, then NVA Troops, then NVA Guerrillas.

VC Shaded Capabilities:

• Cadres: Use the Shift Toward Opposition column of the Space Selection Priorities table to select the first Rally space from among spaces eligible for Agitate, up to Agitate Total. Shift Agitate Total -1 for each Terror marker removed and level shifted.
• Main Force Bns: Remove most US Troops from one eligible Ambush space.