The French columns have so far found tough, aggressive and cunning fighters, but respecting, except for the Kempetai, the rules of elementary humanity during the fights and after. We are now going to have to deal with adversaries who are just as determined and cunning, but showing a cruelty unworthy of a civilized nation:execution of wounded and prisoners, assassinations of civilians, men, women and children, rapes, looting .
From Lao Kay to Mongcai, our border and its surroundings are divided into military territories whose administration is the responsibility of the command. Around the chief towns Lao Kay, Ha Giang, Cao Bang and Mongcai, checkpoints, with mediocre manpower, are established, controlling the main obligatory crossing points (crossroads of tracks, pass, ford). These posts were set up, originally, not to defend a border against the attacks of a modern army - except at Lang Son and Dong Dang -, but to oppose the actions of pirates and smugglers.
A few have been modernized, but the whole remains without much defensive value, and their leaders are fully aware of this. An effort, on the other hand, has been made in recent years to give the main towns the means to resist effectively.
The Lao Kay and Ha Giang garrisons will be surprised on the night of March 9-10. In Lao Kay, the fighting lasted all night and the last fort — Coc Leu — was only returned at the end of the day on March 10 to avoid the massacre of civilian hostages.
Ha Giang will succumb after a night of fighting and part of the garrison will be executed, including the wounded. Skirmishers, escaped or released by the Japanese, will have the most harmful influence on the Indochinese in the posts where they will take refuge.
Cao. Bang, held by two companies, will resist until March 13.
Mongcai (1st T.M.) will be evacuated by our troops on March 21, for lack of supplies necessary to continue the fight.
To obtain the surrender of the posts, once the capital was in their hands, the Japanese let it be known, from Lao Kay and Ha Giang, that “a general order to cease fire was given by the governor general. Anyone who continues the fight will be a rebel and treated as such”.
This false information will only disturb the Indochinese already sensitized by the abandonment and the destruction a priori of a certain number of posts considered unusable for the battle which was announced.
The manpower and supplies of these abandoned posts (Ban Phiet, Pa Kha, Yen Binh Xa, Vinh Thuy, Bac Quang) are grouped together, initially, towards Muong Khuong and Pha Long, on the one hand , Hoang gu Phi, on the other hand.
Liaisons are made with the representative of the French military mission (M.M.F.) in Mapeu, Captain Borg, who is in contact with our mission in Kumming (Commander Sainteny).
The desertion of many Indochinese forces our officers to reorganize the units which thus collect, every day, isolated individuals or small groups of survivors. Pha Long victoriously resisted a first Japanese attack on March 25. The Japanese were also arrested at Ho Pi Chay on March 29. The day before, however, Pha Long fell, in the absence of part of the garrison who had attempted a raid on Xin Man. At the end of March Muong Khuong must be evacuated.
The French presence will nevertheless be maintained for another month in the region. With the additional troops from the posts of Pho Bang, Dong Van, Coc Pan and Bao Lac, evacuated in the second half of March, a relatively large group could be formed (a white company including legionnaires from Tong and Ha Giang, 4 companies of natives, 4 companies of mountain dwellers).
This group, under the orders of Commander Klein, who replaced Captain Borg, reoccupied, after a hard fight, the post of Man Mei (April 25 to May 2), but will have to retreat before the Japanese assaults and following the decisions taken by the Chinese border authorities. These authorities, whose hardening is very clear, at the beginning of May, claim to disarm our elements "who are fighting in a theater of operations that is not theirs".
In Cao Bang, the head of the territory was not surprised by the Japanese attack. Retired on Trung Khanh Phu, he gave himself the possibility of commanding the forces withdrawn from the posts and of maneuvering his adversaries. If Nguyen Binh fell in
the night of March 9 to 10, Ta Lung, reinforced, will resist until the 14. With the personnel of the posts (Ta Lung, Quang Uyen, Dong Khe, Ha Lang, Soc Giang and Tra Linh), Commander Reul will hold Po Peo until March 25. Roaring from Po Peo towards the Soc Giang region, he detached elements near Nguyen Binh and Tra Linh, despite the presence of 3,000 Japanese at Cao Bang. Following the liaisons made with Commander Revol (M.M.F.) in Tsing Tsi, Commander Reul knows that he cannot count on any Allied help.
Lack of arms and ammunition necessary, he will retire to China in the first half of May.
In the 1st military territory, the attack was launched on the night of the 9th to the 10th against our garrisons of Ha Coi and Tien Yen. In the latter locality, the Japanese were repulsed with severe losses. In Ha Coi, the Japanese capture the chief of post, Captain Reynier, during an aperitif to which they have invited him. Led in front of his post, which he had taken care to alert before surrendering at the invitation of the Japanese, the captain made himself known to his deputy and ordered him not to surrender as the Japanese demanded, but to start the fire. When the post fell on March 11, Captain Reynier would be savagely executed in front of what remained of the garrison.
Tien Yen, whose numbers were reinforced by detachments from the navy and the aviation, will hold, thanks to several counter-attacks carried out by the garrison until March 14. The ammunition ran out and the requests for parachute drops made by Lieutenant-Colonel Lecocq not being satisfied, the garrison fell back to Binh Lieu on the night of March 14 to 15.
Lieutenant-Colonel Lecocq, commander of the territory, was killed on the 13th, during an assault on Ha Coi, in Japanese hands since the 11th, but surrounded by his troops. Dam Ha having fallen on the 15th, the Japanese garrison of Ha Coi will be resupplied and reinforced on the 16th. Withdrawn to Mongcai, the French forces are violently attacked, starting on March 19th. New pressing requests for supplies remain without result. The retreat into China, which had become compulsory, began on the 21st. The Indochinese, who had behaved well during the previous battles, then deserted en masse. Our elements will be grouped together under the command of Captain Commentry, whose patrol boats Frezouls, Crayssac and Audacieuse will maintain our colors for a while longer in the territorial waters of the 1st military territory.
A classic passageway between Kouang-Si and Tonkin, Lang Son is the mooring point to which our border defense system hangs. After the fighting in September 1940, its fortified system had been reviewed and modernized. A special effort had been made to provide the forts (“Brière-de-l’Isle”, “Négrier”, “Gallieni”) and the small forts (Ky Lua) with abundant reserves of ammunition and food. The garrison, finally, large (5 battalions. 2 artillery groups) and aware of its strength, has excellent morale