Dien Bien Phu: The Final Gamble


By Stuart McAninch

Designer: Kim Kanger

Publisher: Legion Wargames

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On first examination of the map and rules for Kim Kanger’s game, I was struck with how difficult the task of the Viet Minh player is.   While he has a potent force, he must bludgeon his way through one French strongpoint after another.   And he must do this on a tight time schedule with limited replacements and artillery ammunition and little hope of reinforcements.  A look at French counters indicates strong infantry and artillery.  At this point, I concluded that this is my kind of game.  The game system forces the Viet Minh player in particular to engage in exceedingly thorough operational planning.   What follows is an analysis of the game system and what that analysis suggests regarding a Viet Minh operational plan and tactics for the siege.

Game Description

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This is a siege game which represents the defense of an airstrip by the  equivalent of a  French division against more than three Viet Minh infantry divisions supported by nine artillery battalions.   The setting is a valley located in the highlands near the border between Vietnam and Laos in 1954.  The game is divided into 21 turns, each of which represents three days.  If the French have not surrendered at the end of the last turn, the French player wins.  If they have surrendered, the Viet Minh player wins.  Surrender is checked each turn by roll of two dice once the French perimeter has been reduced by the Viet Minh to a few strongpoints and  “structure hexes” (hexes containing hospitals and central stores of supply).

The map is divided into hexes, each of which is 150 meters across.  The main map depicts the primary French defenses.  Boxes depict the French strongpoints several miles south of the airstrip (which they named “Isabelle”), the ground between Dien Bien Phu and Isabelle, the ground between Dien Bien Phu and a potential French relief force in Laos, and the Viet Minh rear areas.


Analysis of the main map reveals the pattern for the French defenses.  Guarding the approaches to Dien Bien Phu from the north and northeast are two large strongpoints (four hexes each) situated on high ground: Gabrielle and Beatrice respectively.  Neither is within easy support range of other strongpoints.  Closer to the airstrip and structure hexes in the east is a network of strongpoints collectively named “Dominique” and “Eliane” (see the portion of the map below).  Many of these positions are also located on hills.  All are in close proximity to several other strongpoints which can impede a flanking force and serve as staging areas for counterattack or reinforcements in the event of Viet Minh assault.


Immediately northwest and west of the airstrip and structure hexes is a second network:  Anne-Marie, Huguette, Francoise, and Claudine (see the portion of the map below).  The strongpoints to the northwest are not as tightly integrated as the strongpoints to the east are—and are therefore more vulnerable to flanking and isolation.

Around the structure hexes is an inner ring of strongpoints which include the headquarters and protect the reserves and artillery batteries.  Collectively, the structure hexes and most of the inner ring of strongpoints are labelled a “supply area”, which is basically the core of the French position and which possesses certain properties. The French can, for instance, strategically move 6 rather than 4 units during its “Valley move” if all 6 originate within the supply area.


The main map is also divided into areas of operation (“division sectors”) for the Viet Minh divisions:  the 316th and 312 Divisions approaching from the east and the 308th Division from the north.  Moreover, one regiment of the 304th Division is charged with operating against Isabelle.  Each division sector is further divided into trench zones.  Each division begins with zone one in their sector entrenched and will extend their digging sequentially into further zones in that sector as the game proceeds.   Digging cannot extend beyond a zone containing a French-controlled strongpoint—and it is only partially completed (a “dig zone” rather than a “trench zone”) as long as any strongpoint in that zone remains in French control.

In terms of terrain, the map is punctuated by occasional hills.  There is some forest on its eastern edge, but most of the ground is either scrub or rice fields (the second of which slows movement during the latter two thirds of the game due to rain and then monsoon).  Movement is impeded and defense enhanced by the Nam Youm River, which runs through the French defenses between Dominique and Eliane to the east and the supply area to the west.

The game system forces the Viet Minh player in particular to engage in exceedingly thorough operational planning

Each game turn is divided into six phases.  These are then further divided into a total of 31 segments.  Once one becomes accustomed to what occurs in each segment, the game flows smoothly.  Valley and box moves allow each player to reposition a limited number of units without regard to number of hexes.  During several segments, varying numbers of units of one side or the other can move a limited number of movement points.  The French can move units not in strongpoints into strongpoints in the supply area late in the turn regardless of number of hexes.  There are segments for barrage and assault, for Viet Minh replacements and reinforcements, French supply, Viet Minh trench digging, etc.

One notable feature of the game which becomes evident when studying the organization of game turns is that “isolation” of units and strongpoints (which is failure to maintain a “line of communication” to a supply source) results in surrender in less than a turn.   This simulates the consequences of running out of ammunition.  When tracing this line, the French must avoid enemy units and zones of control as well as trench zone hexes not occupied by friendly units.

Combat: Barrages and Assaults

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First, it is important to note that the French and Viet Minh players have different defense fire and assault fire tables and rules for barrage.  This represents different scales (French units are infantry companies, artillery batteries, and mortar and tank platoons while Viet Minh units are infantry and artillery battalions) and other characteristics of the respective armies.  Each player has two barrage segments in a turn:  one preceding the player’s own tactical movement and assault and one preceding the enemy’s assault segment.  In the barrage preceding tactical movement and assault, the enemy can lose strength points and/or become “shaken” (a status which deprives units of their zones of control and negatively affects die roll modifiers in combat).  Barrages preceding enemy assaults provide column shifts for defending units of both sides.   For the French, they also provide a die roll modifier for defending units and the possibility to reduce die roll modifiers for the assaulting enemy unit by rendering supporting units shaken.  The French also receive each turn one airstrike which is conducted as a barrage—with a die roll modifier of one favoring the Viet Minh given the ineffectiveness of French fighters and bombers during the siege.

Assault is the other form of combat.  While a description may make the sequence of die/dice rolls for assault seem convoluted and while the sequence does in fact take some practice in order to master, it actually works quite well.  Assault is conducted by a single unit against a defending unit in an adjacent hex.  Each assault involves four rolls of a die or dice:  a defense fire roll to determine the die roll modifier for the subsequent defense effect roll and an assault fire roll to determine a die roll modifier for the subsequent assault effect roll.  A range of die roll modifiers affect the defense fire and assault fire rolls by being added to or subtracted from the unit’s strength: supporting units and barrages, obstacles to assault (wire for the Viet Minh, uphill and river for either side, and forest for the French), whether the defender is shaken and/or entrenched, and whether the French player has run out of medicine.  The column for the defense effect roll is determined by the morale of the assaulting unit (2-5) and whether there is a support barrage; results range from abort to hesitate attack to normal attack to surprise attack.  Excluding surprise attacks and some aborted attacks, results also include a step loss for the assaulting unit.  The column for the assault effect table is determined by the morale of the defending unit and whether it is shaken.  Moreover, normal attack in effect adds a die roll modifier of one in favor of the assaulting unit; surprise attack adds two.  This final die roll in the assault procedure will result in one of the following outcomes:

*No effect

*Choice (the defender takes a one- or two-step loss or else retreats)

*Loss and retreat

*Two-step loss and retreat.

There are few assaults in any given turn, and the system moves the player away from the common practice in wargames of counting numerical factors to thinking about military factors.  Rather than calculating how many factors are needed to obtain 3-1 odds, the player is channeled by the sequence to consider what the likelihood is of, for instance, dislodging an entrenched and unshaken but reduced strength 4-morale French infantry company—benefitting from support fire from a second unit and an intensive support barrage—in an assault uphill and through wire by one full-strength battalion supported by two more battalions (contingent on them not becoming shaken by French barrages).  Simple calculation of probability of success (how many chances out of 6 or 10 or 36) is impossible prior to actually initiating the assault.

Managing Supply, Reinforcements, Morale, and Replacements

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Both players have tracks surrounding the map to manage.  For the French, these pertain to supply and reinforcement.  French supply is divided into several categories:  French artillery ammunition, food and bullets, medicine, and fuel & spares.  Since the airstrip was rendered useless by preregistered Viet Minh artillery fire, all French supplies during the siege had to be airdropped.  In the game, this entails filling each turn a number of slots for airdrop (initially 18) with the player’s choice of supplies in each of these categories.  One slot can be filled with replacements (which enable the replacement of one step loss of infantry and one of artillery or tanks).  Any reinforcements also need to be assigned slots.  During the game, slots decrease as a result of weather.  Rain during the middle 7 turns decreases slots by 1; monsoon decreases them by 3 more during the last 7 turns.  They further decrease as the result of the extension of the Viet Minh trench system.  Moreover, if a French relief force does advance through the Laos boxes toward Dien Bien Phu, 5 more slots are lost as transport planes would have to be diverted to supply that force.

To make logistics even worse for the French, airdrops are often aborted:  a die roll each turn can result in 0 or as many as 3, 6, or 9 aborts.  And there are at least two other die rolls every turn, each of which usually results in the loss of the equivalent of one slot of supplies.  Supplies in each category are expended each turn, and the penalty for running out of supplies in any of them is severe.  Finally, the French begin the game with 9 factors of trucks for moving supplies.  These are gradually lost during Viet Minh bombardment.  When the number of factors falls below 4, the ability to receive artillery ammunition or replacement parts for artillery and tanks progressively decreases.


French reinforcements consist of five excellent 4-company parachute infantry battalions.  These units represented the vast majority of France’s airmobile reserves in Indochina, and the central command was not inclined to commit them lightly.  This reluctance is well reflected in the game.  There is a four-space track for French reinforcements with the French marker being advanced one space for every infantry company lost.  At the fourth space, though, reinforcement is not automatic.  A die is rolled and the result (in the majority of cases on a roll of 1 or 2) can be a reinforcing battalion.  However, it also can be movement back one space (“Perhaps, we shall look into it”) or two spaces (“Not now, we can’t spare one”).  Even after reinforcements are authorized and assigned slots for airdrop, there is still possibility of delay due to an aborted airdrop.

The Viet Minh, operating far from their supply bases and having to move supplies with limited equipment on poor roads and tracks, also have to carefully ration artillery ammunition recorded on an ammunition track.  The Viet Minh player receives each turn ammunition for 5 barrages (which decreases to 3 during monsoon turns).   On some turns, the player is able to add a 6th by die roll with this representing the Viet Minh occasionally being able to get to airdropped French shells compatible with their guns before the French could.

If the French player has to carefully manage supply, the Viet Minh player has to as carefully manage morale

The Viet Minh also have tracks for morale and replacements.   All Viet Minh battalions begin the game with morale of 5.  However, that morale is variable.  On the morale track, there is a marker for each Viet Minh division.  Morale declines one space for every replacement fed into a given division to reverse a step loss.  If the decline is six spaces, then morale for the division drops from 5 to 4.  A decline of six more spaces drops morale to 3.  And so forth.  Morale can be recovered by not participating in an assault in a given turn (one space).  An additional space can be recovered by also not being adjacent to French units.  There is a chance that an additional space for one division can be recovered by a die roll resulting in capture of airdropped French medicine, food & bullets, or fuel & spares rather than capture of artillery ammunition.  The Viet Minh ability to recover morale is lessened, however, if the Viet Minh player is not able to keep to an ambitious pace for gaining control of strongpoints—at least two hexes per turn with temporary extra credit for those captured during the previous turn.  If the French player has to carefully manage supply, the Viet Minh player has to as carefully manage morale.

The Viet Minh player has 90 replacement points for the game.  In addition to using these to replace step losses, the player must expend two points per monsoon turn to replace troops lost to disease.  There are few reinforcements, and drawing them comes at a cost:  either leaving the door from Laos for a French relief force open or else reducing artillery ammunition supply (by drawing the regiment providing security and manpower for it).

The Respective Armies


The Viet Minh force consists of three full infantry divisions and part of a fourth.  Each full infantry division consists of 9 battalions organized into 3 regiments as well as the division’s heavy weapons capability.  Each battalion has 3 steps and has a combat strength of 9 when at full strength.  Given the size of units (battalions rather than companies), they cannot be stacked.  Morale, as stated earlier, is initially 5 (and keeping it at 5 has to be a high priority for the Viet Minh player).  The heavy weapons capability is one barrage within two hexes of any battalion (if, of course, an ammunition point is expended for it).  The part of the fourth division is a 3-battalion regiment of the 304th Division assigned to operate against Isabelle to the south of Bien Dien Phu.  At full strength and morale, this is a formidable attack force.

The Viet Minh also have 9 battalions of artillery (augmented by the heavy weapons for the four divisions).  The artillery is off-board and cannot be reduced by counterbattery fire or airstrike (which is historically accurate).  Artillery fire against strongpoints was methodically preregistered and lethal.  This is reflected in the game by artillery fire (but not heavy weapons fire) during the Viet Minh barrage segment being limited to French strongpoints or adjacent hexes. The fire of both artillery battalions and divisional heavy weapons affects the hex designated for barrage as well as the six surrounding hexes.  Two dice are rolled for each hex occupied by French troops with one determining whether some or all units in a hex are shaken (the die roll being equal or above the morale rating of a unit in the hex designated for barrage and above the rating in all other hexes).  The other determines whether a step loss occurs.  The more French steps there are within the 7-hex barrage zone, the greater the chance of a step loss is.  Depending on the concentration of French troops and their morale, barrages during this segment can dramatically weaken defense of a strongpoint prior to infantry assault.  Barrages in support of infantry battalions under assault are less dramatic in their impact but still important.


The French force consists of infantry companies, artillery batteries, and tank and heavy mortar platoons.  The French can stack up to three units per hex.  Unit morale varies between 2 and 5.  The companies of the two parachute infantry battalions which begin the game at Dien Bien Phu (as well as two other companies) have morale of 5.  Five infantry battalions (mostly Foreign Legion) have morale of 4.  Other infantry battalions (including most north African units) have morale of 3.    One of two Thai battalions as well as 12 independent Thai companies (the Thai units being recruited among highlanders from the region) have a morale of 2.  Companies have two steps.  The combat strength of most 4- and 5-morale units at full complement is 7; the combat strength of those with a morale of 2 or 3 is less (as few as 4 for independent Thai companies).  Reduction of a unit by a step only results in the loss of 1 combat factor.

There are 16 batteries or platoons capable of barrages.  Unlike Viet Minh barrages, French barrages only include one hex.  However, an intensive barrage (requiring 2 ammunition points instead of 1and adding 1 to the die roll modifier) can be particularly lethal in terms of shaking a battalion and reducing it a step.  Three platoons of tanks provide excellent support for assaults or defense against assaults (a die roll modifier of 2 each when conducting the French defense or assault fire roll).

The numerous French support troops present during the siege are handled abstractly in the game.  Viet Minh movement in a supply area is limited to a single hex (5 movement points) due to resistance by those troops.

Lessons Learned About Operational Planning and Tactics in the Game  dbp_central-01_ng

To put the problem of operational planning in the game simply, the burden is solely on the Viet Minh player.  The French player is charged with setting the best defense possible and reacting to what the Viet Minh player has planned and is trying to implement.  Before examining Viet Minh operational planning, it is useful to examine several historical and/or game realities:

The bottom line is (as the Viet Minh senior commanders themselves found out after the initial assaults in the siege) that human wave tactics characterized by indiscriminate assaults on strongpoints do not work.

Assaults are expensive in terms of step losses and replacement points.  The Viet Minh will not often avoid a step loss on the French Defense Effect die roll; “Surprise” is a relatively rare result.  Moreover, if the Viet Minh player commits other battalions from the same regiment to support the assault (and gain a die roll modifier per battalion in the roll of the dice on the Assault Fire Table), those battalions are subject to barrage.  Consequently, if the Viet Minh player commits two supporting battalions to an assault, he will be lucky to only suffer one step loss.  It is essential when planning assaults to keep in mind that the Viet Minh receive only 90  replacement points for a 21-turn game—and, more realistically, 76 replacement points when one subtracts the 14 which are deducted for illness during the 7 monsoon turns.  On average, then, the Viet Minh player has less than 4 replacement points to commit per turn.  Consideration has also to be given to effects on morale:  if two steps are lost in a single assault, replacing those steps will move that division’s morale two steps down on the morale track.  The good news for the Viet Minh player is  that in the case of multi-hex strongpoints, not every hex has to be taken by assault.  On occasion, a hex can be cleared of defenders by well-planned barrages.  However, even if defenders remain in one or more hex after barrages and assaults, the French player may decide to cut losses and withdraw if the Viet Minh player is able to make the situation sufficiently dire.   The bottom line is (as the Viet Minh senior commanders themselves found out after the initial assaults in the siege) that human wave tactics characterized by indiscriminate assaults on strongpoints do not work.  Assaults have to be carefully planned in terms of likelihood of success and casualties and employed sparingly.  Alternatives to assault need to be developed.



One primary alternative to assault in the 308th Division area of operation in the northwest and west is suggested by how the boundaries between trench zones are determined in that part of the map.  Typically, zones in this area extend for 150-300 meters (1-2 hexes) behind a strongpoint.  Digging can extend into a zone with a French-controlled strongpoint but not into a subsequent zone.  Viet Minh troops are considered entrenched in such a “Dig zone”.  This means that with sufficient troops, the Viet Minh player can have the benefits of entrenchment while completely surrounding a French-controlled strongpoint.  The onus is then placed on the French player to restore a line of communication.  He can assault with a relief force (see the photograph below).  He can attempt to break out with the garrison.  He can do both.  But if this effort is unsuccessful, the garrison surrenders late in the same turn that it is surrounded.  Control of the strongpoint switches to the Viet Minh.  Viet Minh barrages and assaults may be desirable in order to weaken the garrison and discourage counterattacks, but they are not necessary for this tactic to work.  This suggests that the 308th Division area might be the logical site for the initial Viet Minh offensive.



Barrages are a potent means for attriting French forces—particularly where the French player concentrates troops to defend a strongpoint.  Attrition can be direct through loss of strength points to barrages, but it can also be indirect through weakening defenders in a strongpoint hex sufficiently so that they become an easy target during the following assault.  Such attrition can force the French player to thin his defenses over time.  It is not particularly difficult for the Viet Minh player to cause more casualties than can be substituted for by replacements, reinforcements, or soldiers returning to duty from the hospitals.

While the map is divided into areas of operation for the Viet Minh divisions, there is no rule requiring units of a division to remain in that area of operation.  Given that 3 battalions can be moved without regard to number of hexes each turn during the “Valley move”, a formidable force can be concentrated over several turns in one division’s area.  In order to restore morale, divisions can alternate turns for assaults.  Overwhelming numbers can be committed to envelopment of a single strongpoint.  While this may not guarantee an immediate fall of the strongpoint, it definitely makes the French job of relieving and holding it more difficult.


Isabelle, the large circular network of 6 one-hex strongpoints surrounding a single-hex supply area south of Dien Bien Phu, is a tough nut to crack.  At first glance, Isabelle may seem like a tempting target for attrition by barrage and subsequent assaults.  Isabelle was obviously premised on the assumption that Viet Minh artillery could be neutralized by counterbattery fire and airstrikes (a faulty assumption given Viet Minh ingenuity in transporting guns through the wilderness and fortifying them).  The defending two battalions, two batteries, tank platoon, and supporting Thai units are densely packed; the position is a killing ground for Viet Minh artillery.  With the support of French artillery, though, even a decimated garrison can hold on tenaciously and counterattack when a strongpoint falls.  Moreover, Viet Minh barrages, digging, and troops diverted to assist the one regiment tasked with operating against Isabelle take away from the main effort against Dien Bien Phu itself.

dien+bien+phu+1954Considering these realities does suggest a Viet Minh plan of operations.  Avoid shelling or assaulting Isabelle.  Make the objective for the first turn taking Gabrielle and Beatrice, which opens two divisional areas to further digging (including the especially important 308th Division area northwest and west of Dien Bien Phu).  Use valley movement during the first three turns to transfer 3 regiments (9 battalions) from the 312th and 316th Divisions to support the attack by the 308th.  Concentrate digging there during the early turns.  Take full advantage of the ability to dig behind strongpoints in order to envelop them.  As the French player suffers attrition and is forced to thin his defenses in the east to replace losses in the west, begin to send units back to the sectors of the 312th and 316th Divisions.  Shift digging to one of those operational areas.   Coordinated assaults now should be launched against weakened strongpoints in the areas of the 308th and either the 312th or 316th.

The pace of the operation cannot be leisurely.  If the Viet Minh player does not average control of 2 additional hexes of strongpoints per turn, restoring morale of divisions becomes more difficult.  Moreover, while the Viet Minh player has 21 turns to reduce the French position sufficiently to force surrender, the last 7 turns are monsoon.  Barrages will lessen during those turns as less artillery ammunition arrives.  As a consequence, the ability for artillery to soften up French strongpoints prior to assault will obviously diminish.


And, of course, an able French player will not passively sit by and simply allow the Viet Minh player to implement his plan.  French artillery, which is quite good, will create step losses among supporting battalions for assaults and die roll modifiers for defending units as well as weaken Viet Minh positions prior to counterattacks.  A counterattack launched by a parachute infantry battalion from the French central reserve supported by tanks is a thing to be feared by his opponent.  While it is not guaranteed to force retreat from a vital position, it affords a very good chance of doing so.

In allocating troops to strongpoints, the French player has several basic decisions to make.  One has to do with troop density.  He can stack up to 3 units in a given hex.  Does he elect to stack units and thereby increase losses to barrages?  Or does he choose instead to minimize the number of units and thereby reduce defensive capability against assault—and also increase the possibility of a hex being lost to barrages if the Viet Minh player experiences a couple of lucky die rolls?  Another has to do with troop quality.  Under what conditions does the player commit elite parachute infantry companies (initially only 8) to strongpoint defense rather than the reserve for counterattacks?  Where does the player commit his next best units (4-morale infantry companies)?  How does he best employ his 2-morale Thai troops?  Does he place mortar platoons in strongpoints likely to be attacked despite their low defense capability against assaults?


Two rules should help frame the French player’s decisions on these matters.  The first one has to do with how casualties in Viet Minh barrages are determined:  the Viet Minh player decides on odd die rolls, and the French player decides on even rolls.  Therefore, having one or two Thai companies mixed with higher morale units provides the French player with a less painful alternative when selecting a unit for step loss on an even roll.  The second rule states that a French replacement unit brought in by airdrop replaces a step loss for a tank or artillery unit (including mortar platoons) as well as a step loss of infantry.  Hence, a mortar platoon (or artillery battery, for that matter) could be used for a step loss and ultimately regain that step while an infantry unit also regains a step from the same replacement unit.  Yet another consideration is that serious defense of a strongpoint hex against assault really requires a defending unit which is a 4- or 5-morale infantry company.  A 3-morale company is marginal, and a 2-morale company is very unlikely to hold the position.


The French player will be continually faced with the question of whether to attempt to hold or withdraw from a partially overrun and/or surrounded position.  Attempting to hold almost certainly will require counterattack and/or reinforcement and will result in considerable casualties.   If my counterattack breaks through the cordon around Anne-Marie, do I reinforce for another turn of battle (and risk failure to break through next time and surrender) or do I evacuate the garrison while I have the chance?  If I lose two of four hexes of Beatrice, do I simply hold the remaining two, counterattack, or withdraw completely?  While every situation will be different, there will be occasions when loss of a particular strongpoint will be painful enough in terms of increasing vulnerability of nearby strongpoints to warrant counterattack and reinforcement.  And the French player will need to choose his spots to hold fast and engage in battles of attrition in order to disrupt Viet Minh momentum.


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This is an outstanding game.  There is nothing in the game which I could find that is “gamey” and absurdly ahistorical.   The balance between that which the design leaves to the player to decide and that which is abstracted is very good.  The players are left to manage the siege or disruption of the siege without having to micromanage logistics, trench digging, etc.  The problems facing players are fascinating, and likely solutions do not seem to violate what was historically feasible.  Kim Kanger is obviously highly creative in adapting conventional game mechanics (or developing new ones) to solve design problems and in integrating those mechanics into a game system that works.  For me, the greatest joy of the game is the opportunities for careful operational planning it affords.


About the Author

Stuart McAninch

Wargaming was a gateway into the serious study of history for Stuart during junior high  and high school in the 1960’s.  He was able to continue playing sporadically after high school and was particularly fortunate to find an active wargaming group in the mid 1980’s while studying for his doctorate in history of education at the University of Illinois.  After a hiatus of more than 25 years for family and teaching, he returned to wargaming in late 2013.  Although new design mechanics, such as  card-driven wargames, took him time to get used to, he is adjusting. He is now retired in Middlebury, VT and plays with a small local group of gamers.

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