The 'Battle of Tachiao' between Japanese and Chinese forces was the first of the three clashes that together constituted the 'Battle of Yunnan and the Burma Road' in the Burma campaign (18/19 March 1942).

Advanced elements of Major General Dai An-lan’s Chinese 200^th Division arrived in Toungoo on 8 March 1942 and took over defensive positions from the British forces. Toungoo itself was to be the main defensive position of the Chinese forces, with an outpost a short distance to the south at Oktwin. Dai sent the division’s motorised cavalry regiment and 1^st Company, 598^th Regiment to the banks of the Kan river 35 miles (56 km) to the south of Toungoo and 12 miles (19 km) to the south of Pyu. The cavalry regiment, together with one company of the infantry regiment, pushed up to the Kan river, a platoon of cyclists then taking up positions at the bridge over the river.

At first light on 18 March, about 200 Japanese reconnaissance troops of the 143^rd Regiment of the 15^th Army's 55^th Division, commanded by Lieutenant General Hiroshi Takeuchi, advanced right up to the bridge on motorcycles. Reaching the outposts, the Japanese were ambushed by the Chinese troops hiding along the sides of the road. Chinese armoured cars joined the attack and after three hours of fighting the Japanese fell back, leaving some 30 dead together with some 20 rifles, two light machine guns and some 19 motorcycles. After fall of night, the Japanese continued their attacks with small units, and the Chinese covering force fell back toward their line at Oktwin. The Japanese followed on the next day, and took Pyu on 19 March.