[12] In September 1937, Hideki Tojo sent the Japanese army stationed in Chahar to invade Shanxi in order to exploit its resources.

The city of Datong fell, and the NRA was forced to go on the defensive, and concentrated their troops along the Great Wall in battles at places like Pingxingguan and to the east at Niangziguan.

[citation needed] On September 21, 1937, Major Hiroshi Miwa, commander of the 1st Daitai, 16th Hiko Rentai of the IJAAF, who was a former-hired military flight instructor for Zhang Xueliang's Fengtian army air corps and well known in the Chinese military aviation circles of the time, led 7 Kawasaki Ki-10 fighters on an escort mission for 14 Mitsubishi Ki-2 bombers to attack the city of Taiyuan, encountered Chinese Air Force V-65C Corsairs and Curtiss Hawk IIs, shooting down several, however Major Miwa himself was shot down and killed over Taiyuan in a duel with Captain Chan Kee-Wong, commander of the 28th PS, 5th PG whilst flying a Curtiss Hawk II.

[citation needed] On October 8, Chiang Kai-shek ordered two armies, a Corps and a division to defend the Ladies Pass, a critical point on the rail line to Taiyuan.

The Japanese managed to hold their ground despite sustaining severe losses, and the Chinese retreated back to the main defensive point at Ladies pass on October 22.

[13] On October 13, the Japanese 5th Division and the Chahar Expeditionary Force, supported by air and heavy artillery bombardments, attacked the Chinese defenses North of Taiyuan.

The Chinese defenders had entrenched themselves in prepared fortifications, and managed to hold the Japanese off for ten days in fierce hand-to-hand fighting.

The Chinese units conducted an orderly retreat and took up positions atop the high ground on the Blue Dragon Ridge, 20 miles north of Taiyuan.

[14] The Chinese managed to fight for another five days, but on November 2, Japanese engineers tunneled under Tungshan and set off a series of charges beneath it.

By the morning of November 9, those soldiers and civilians that still remained jammed in the southwest gate and the sole bridge were strafed and bombed by Japanese planes, killing and injuring countless people.