Operation Nekka

Defense of the Great Wall
Part of the Inner Mongolia Campaign, Second Sino-Japanese War
Date January 1 – May 31, 1933 Location Eastern end of the Great Wall of China Result Japanese and Manchukuo victory; Tanggu Truce
Belligerents
China	Japan  Manchukuo
Commanders and leaders
Chiang Kai-shek Zhang Xueliang He Yingqin Song Zheyuan	Nobuyoshi Muto Chang Hai-peng
Strength
Northeastern Army: 50,000+	Japan: 50,000 Manchukuo: 42,000
Casualties and losses
Unknown	Unknown

The Defense of the Great Wall (simplified Chinese: 长城抗战; traditional Chinese: 長城抗戰; pinyin: Chángchéng Kàngzhàn) (January 1 – May 31, 1933) was a campaign between the armies of Republic of China and Empire of Japan, which took place before the Second Sino-Japanese War officially commenced in 1937. It is known in Japanese as Operation Nekka (熱河作戦, Nekka Sakusen^?) and in many English sources as the First Battle of Hopei.

During this campaign, Japan successfully captured the Inner Mongolian province of Rehe from the Chinese warlord Zhang Xueliang and annexed it to the new state of Manchukuo, whose southern frontier was thus extended to the Great Wall of China.

Shanhaiguan is the fortified eastern end of the Great Wall of China, where the Great Wall meets the ocean. Per the terms of the 1901 Boxer Rebellion accord, the Imperial Japanese Army maintained a small garrison of around 200 men at Shanhaiguan. On the night of 1 January 1933, the Japanese garrison commander staged an "incident" by exploding a few hand grenades and firing a few shots. The Kwantung Army used this as an excuse to demand that the Chinese 626th Regiment of the Northeastern Army, guarding Shanhaiguan, evacuate the pass defenses.

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