<figcaption>The <span class="caps">RC<span class="numbers">4</span></span></figcaption>

Octo­ber 2020 marks the 70^th anniver­sary of the Bat­tle of Route Colo­niale 4 (RC4), a major defeat for the French Expe­di­tionary Force in Indochi­na along with Dien Bien Phu. Secret Indochi­na has been devel­op­ing pro­grams in the area of the for­mer RC4 between Cao Bang and Ha Giang for some time, and to mark the anniver­sary we take a look back on this famous bat­tle and the regions of north­east­ern Viet­nam where it took place.

The first major offen­sive of the First Indochi­na War took place on July 25, 1948 on the RC3 dur­ing an attack on the Phu Tong Hoa post. More than 3,000 Viet Minh infantry troops launched a night­time attack on the post, which was locat­ed near Bac Khan at the cross­ing of the Ba Be Road. At dawn, the Legion­naires were still resist­ing, and the attack­ers with­drew. After this attack, French gen­er­als decid­ed to evac­u­ate the RC3 and gath­ered their forces on the Cao Bang – Lang Son axis. The Viet­namese opt­ed for a strat­e­gy based on harass­ing the French troops, and to do so they estab­lished the 174^th Reg­i­ment (the RC4 reg­i­ment), com­mand­ed by the famous Colonel Dang Van Viet, who was also known as the Grey Tiger of RC4, the Viet­namese Napoleon, the King of RC4, and the Star­less Gen­er­al. For their part, the French chose to rein­force and for­ti­fy the instal­la­tions along the RC4 axis.

<img alt="'La 317ème section' Movie" src="https://www.secretindochina.com/upload-images/programmes/the-battle-of-the-route-coloniale-4/cao%20bang%20-1604637266.jpg" />
<figcaption><span class="pull-double">“</span>La <span class="numbers">317</span><sup class="ordinal">ème</sup> sec­tion” Movie</figcaption>

The road became the blood­i­est in Indochi­na. Called the Boule­vard de la Mort (the Death Avenue), the bloody road wound beneath rocky cliffs along steep pass­es with bush-cov­ered heights – lend­ing itself per­fect­ly to ambush­es. Con­voys head­ing for Cao Bang loaded with food, ammu­ni­tion, and civil­ians, were reg­u­lar­ly attacked. A few gar­ri­son towns punc­tu­at­ed the route, includ­ing Dong Khe and That Khe. In June 1949, Gen­er­al Revers pro­posed a plan to aban­don the bor­der zone, but it was reject­ed by M. Pignon, French High Com­mis­sion­er in Indochi­na, who viewed a retreat as a loss of face. In 1950, after more suc­cess­ful attacks by the Viet Minh, Gen­er­al Revers’ plan for evac­u­a­tion was adopt­ed, but it was too late. Giap and Colonel Viet adopt­ed the prin­ci­ples of Sun Tzu’s Art of War: The ene­my advances, we retreat. The ene­my stops, we harass him. The ene­my is tired, we attack him. Ene­my retreats, we pursue.

The new chief of staff, Gen­er­al Car­pen­tier, was unfa­mil­iar with the coun­try and ter­rain. He devel­oped a plan to draw the Viet Minh toward Thaï Nguyen (Oper­a­tion Seal), while one col­umn evac­u­at­ed Cao Bang city and a sec­ond relief col­umn from Lang Son (con­sist­ing of the Char­ton and Lep­age columns) joined it at the RC4 town Dong Khe in Oper­a­tion Tiznit. The plan turned out to be dis­as­trous. The two columns could not meet up and were quick­ly divid­ed into sub-columns scat­tered in the bush.

<figcaption>Ho Chi Minh in his mountain</figcaption>

The bat­tle of RC4 was not a clas­sic bat­tle, but a series of dead­ly ambush­es, attacks, coun­ter­at­tacks, and relent­less pur­suits. It played out from Octo­ber 1 – 8 around the lime­stone of Dong Khe. The dec­i­mat­ed, starv­ing Lep­age relief col­umn made up of the 11^th Tabor and the BEP regrouped on Octo­ber 6 at Coc Xa after fight­ing at Na Keo. Coc Xa, a dark cir­cus dom­i­nat­ed by high cliffs with only one exit – a nar­row pas­sage called the Spring (la Source) – became the site of the blood­i­est assault of the Indochi­nese War. At Coc Xa, the French real­ized that they were sur­round­ed by Bat­tal­ions 249 and 308 of the Viet Minh, and that the only way out was to force the Spring passage.

<img alt="The Grey Tiger of RC4" src="https://www.secretindochina.com/upload-images/programmes/the-battle-of-the-route-coloniale-4/TIGRE%20GRIS%20DE%20LA%20RC4-1604638060.jpg" />
<figcaption>The Grey Tiger of <span class="caps">RC<span class="numbers">4</span></span></figcaption>

On Octo­ber 7 just before dawn, the BEP unblocked the Spring at a huge cost: the death of all the com­pa­ny com­man­ders and many legion­naires. Between Octo­ber 7 and 8, Colonel Viet and the Viet Minh con­tin­ued dis­man­tling the two columns, which had devolved into small groups scat­tered and lost in the bush. Only a few units man­aged to pass through the Viet Minh appa­ra­tus and reach the vil­lage of That Khe, which was evac­u­at­ed on Octo­ber 10, fol­lowed by Lang Son on the 17^th. The dis­as­ter of Cao Bang result­ed in the anni­hi­la­tion of the Char­ton and Lep­age columns. Some 5,000 mem­bers of the Expe­di­tionary Force were killed or wound­ed, and of the 3,000 pris­on­ers tak­en, only 1,000 returned.

Since the ear­ly 1990s, Secret Indochi­na has been active in the province of Cao Bang and its neigh­bor, Ha Giang. Activ­i­ties have focused pri­mar­i­ly on the peo­ple and cer­tain mas­sifs, includ­ing Phu Tha Ca, Can Ty, Thong Nong and Mo Xat. We have devel­oped trekking and immer­sive pro­grams there as well as remem­brance pro­grams for bat­tle sites, includ­ing the famous Coc Xa cir­cus, ancient fortress­es, and French fortress­es such as the Du Gia cas­tle in Ha Giang.