Surrounded at Lang Son
25/9/40
On 22/9/40 columns from the IJA 5th Division under Lieutenant-General Akihito Nakamura moved over the border from China to Vichy Indochina at three places and closed in on Lang Son, This contravened the recently signed agreement between the between the two powers and lead to hostilities.
The central column overran the French border defences and occupied Dong Dan immediately north of Lang Son on 23/9/40. The southern column took Loc Bihn pushing back elements of the 9e RIC . The southern attack swung north to support the attack on Lang Son from the south.
On the 24th Vichy General Mennarat sought permission to withdraw from Lang Son but this was denied by the HQ in Hanoi. The Japanese took advantage of the confusion to push closer to the town
The final Japanese assault started at 05:30 on the 25th September
Lang Son, post war US Army map from: http://www.nexus.net/~911gfx/sea-ao.html
Map and Order of Battle
Vichy French Deployment
The II/5e REI and I/3e RTT are deployed in the areas indicated on the map. All personnel stands are dug in foxholes
The Section de Commandement de Brigade is deployed in the Brière de l'Isle
The Batterie Artillerie Lourde Fortresse is deployed at Négrier. The guns are fixed in a gun pit that gives (almost) 360deg arc of fire and -3 cover
The I/9e RIC and 2e Groupe 4e RAC can be deployed in either indicated deployment zone. They must be over 9" from the outsize edge of the zone or within a BUA. They may not be in the bunkers, they are not dug in.
Japanese Deployment
The majority of the 21st Infantry Regiment enters the table turn 1. 1st Bttn 21st Infantry enters between points A & B. 2nd Bttn 21st Infantry enters between points B & C. The 2nd Company 14th Tank Regiment can accompany either infantry regiment. The RHQ and Regimental Gun Company enter turn 2 between points A & C
The majority of the 11th Infantry Regiment enter the table turn 2. 1st Bttn 11th Infantry enters between points F & G. 2nd Bttn 11th Infantry enters between points E & F. The 1st Company 14th Tank Regiment is with the 2nd Battalion. The RHQ and Regimental Gun Company enter turn 3 between points E & F
The observer for the 5th Artillery Regiment starts on table at point D
Terrain
The table is 5ft x 6.5ft if playing at 1" = 50m
The open ground is fairly bare farmland. There are a few scattered clumps of scrub (2" blobs). these are mostly along the roads and rivers (circa 6" apart) buy there will be a smattering in the open areas
The thick red line is the main road. The pink lines are tracks. The tracks do not give a road bonus.
The black dotted line is a railway, it has no game effects
The thick blue line (HI) is the My Mong river, it is only easily crossable at the bridge. However there are plenty of boats around allowing for a an extemporised crossing. Any personnel or Japanese class I gun that wishes to cross the river, if adjacent, may roll d10 at the stat of the movement phase. On a 6+ it may cross taking 2 BMA to do so. If it fails the crossing then no stand may attempt a roll within 3" for the rest of the game
Note the bridge over the My Mong is a combined rail/road bridge
The thin blue line is a stream. It is no impediment to most stands but wheeled vehicles and man-handled guns take a BMA to cross. Stands in the steam get -2 cover.
The dashed sandy lines are ridgelines. They break LOS and allow AFVs hull down positions
The dashed grey lines are the citadel walls. They break LOS. Stands inside the citadel can fire out if touching the wall. Stands outside the citadel can only fire at stands within if they are touching the wall. Stands being shot at gain -3 cover. Stands crossing the wall leaving the citadel and French stands entering the citadel take 1 BMA (actually they are moving to a gate). Japanese stands entering the citadel take 2 BMA. No Japanese vehicles or guns may enter the citadel. Note the citadel wall continues around the the entire circumference of the dark grey BUA.
The dashed brown lines are paths through the hills. They may be moved along as if open terrain. Stands on the path still count as in the woods so get +1 cover. Max visibility down the path is 4"
The green areas are mountainous and mostly covered with trees. Only personnel stands may enter (not man handled guns) and they move at 1/3rd speed. Visibility within is 4"
The pale grey squares are brick BUA, which give -3 cover
The brown squares are wooden BUA that give -2 cover
The dark grey square is part of the citadel, see above for the rules on the walls. Within are buildings giving -3 cover.
The simple town fighting rules are in effect
The small grey squares are bunkers giving -5 cover. Those guarding the Brière de l'Isle are dug in to a cliff face and only shoot north (180 deg). They can only be attacked from the north. The other bunkers have a 360deg arc. Any French personnel stand within a bunker is treated as an MMG stand. There is no scrub within 9" of a bunker.
The grey circles are shelters. They are built into the cliff side and hold one stand each. Those stands can only be attacked by close assault up the path indicated. Stands in the shelters may not fire except at stands close assaulting. Stands attacking and defending both get a ROF of 0.
Air Support
The Japanese had copious air support, the Vichy had almost nothing.
On turn 1 the Japanese automatically get 1 Ki-27 Fighter and 1 Ki-30 Attack.
On turn 2 onwards both sides roll d10, the Japanese get air support on a 8+, the French on 10. The Japanese may get many air missions, for the French each plane type may only appear once
Roll to see what planes arrive: Japan: 1-4: Ki-27 Fighter, 5-8: Ki-30 Attack, 9-10 Ki-27 & Ki-30. Vichy: 1-7 Potez 25 Light Attack, 8-10 Potez 25 & MS.406 Fighter.
Special Rules
The game lasts 11 turns (to 10:30) with a possible extra 12th turn. Roll at the end of turn 11, on a 6+ there is an additional turn
The Batterie Artillerie Lourde Fortresse is in a fixed position. The gun covers the yellow area. Its high up so can see over all intervening terrain, though there is a 3" dead zone behind the BUA's. The gun pit is immediately in front of the Négrier shelter. If the gun crew are forced back they will always be force back in to the shelter.
Point D is a high observation point. Any observer will have LOS over the entire table except where blocked by woods. BUA have a 3" dead zone behind them.
Japanese Infiltration. Just before the orders phase of turn 3 the Japanese player rolls 1d10. On a 8+ they may place a self ordered Japanese infantry stand within the woods woods between points G & H. The stand must be placed out of LOS of all French stands. The Japanese player may roll each turn.
Victory Conditions
The French are keen to preserve their retreat route and the Japanese to cut it. Victory is measured after the end of the last turn
If the French have any stands in good morale north of the river FI they win a decisive victory. This condition trumps all others
If the Japanese have one or more personal stands in good morale touching road XH they win a minor victory
If the Japanese have three or more personnel stands and at least one AFV stand, all in good morale, touching road XH they win a decisive victory (this trumps the minor condition)
Any other result is a French victory
Good morale means not shaken and not demoralised
References
Axis History Forum: http://forum.axishistory.com/viewtopic.php?f=65&t=115786&view=unread#unread & http://forum.axishistory.com/viewtopic.php?f=65&t=102115&start=45
5e REI: http://laguerreenindochine.forumactif.net/t388-5e-regiment-etranger-dinfanterie
French Army 1939-1940 Order of Battle Vols I-VI; Lee Sharp
French Tanks and AFVs in Indochina, 1919-45: http://france1940.free.fr/vichy/tk_indo.html
Index de la Fortification Francaise 1874 - 1914: http://iff.fortiff.be/index.php?page=l148
Indochine 39-45, l'Incident de Lang-Son: http://aerostories2.free.fr/acrobat/events/langson.pdf
La Légion Etrangère en Indochine entre 1939 et 1945: http://www.anai-asso.org/NET/document/le_temps_de_la_guerre/le_temps_de_la_guerre_19401955/2_guerre_indochine/la_legion_etrangere_en_extremeorient_19391945/index.htm
Order of Battle: http://en.wikipedia.org/wiki/Indochina_Expedition_order_of_battle
Vichy Indo-China vs Japan, 1940 - http://stonebooks.com/history/vichyvsjapan.shtml