The Second Sino-Japanese War, started in 1937, revived a perceived sense of patriotism in the local Chinese to their native homeland in China which led them to impose an embargo against Japanese goods and products in Singapore. During the war, many of the immigrants returned to China to fight the Japanese, while established entrepreneurs sent economic aid or military equipment to China. After the Japanese took Singapore in 1942, the Kempeitai tracked down many Chinese who aided the Chinese war effort against Japan. However, the Kempeitai's Sook Ching Operation was simply a massacre designed to drive fear into the local populace, so the Kempeitai simply picked out people based on accounts of masked informers, which in many cases were false accounts based on personal vendettas. There was also active anti-Japanese resistance during the war, such as Force 136, headed by Lim Bo Seng.