The "Double Tenth incident" ( ) or "Double Tenth massacre" occurred on 10 October 1943, during the Second World War Japanese occupation of Singapore. The Kenpeitai—Japanese military police—arrested and tortured fifty-seven civilians and civilian internees on suspicion of their involvement in a raid on Singapore Harbour that had been carried out by Anglo-Australian commandos from Operation Jaywick. Three Japanese ships were sunk and three were damaged, but none of those arrested and tortured had participated in the raid, nor had any knowledge of it. Fifteen of them died in Singapore's Changi Prison.
After the war ended, twenty-one of the Kenpeitai involved were charged with war crimes. Eight received the death sentence, seven were acquitted, and the remainder were given prison sentences varying from one year to life.
History
In 1943, a special branch of the Kenpeitai under Lieutenant Colonel Haruzō Sumida was charged with finding the culprits responsible for acts of sabotage in Singapore, mainly the cutting of telephone lines and the burning of warehouses. Sumida strongly suspected that the saboteurs were being organised by internees in Changi Prison, and made preparations for a raid on the prison to catch the ringleaders. Sumida's chief suspect was British barrister Rob Heeley Scott, a prominent Foreign Office employee who had previously been detained for his anti-Japanese propaganda, released by the Kenpeitai, and then later sent to Changi Prison.
However, neither Scott nor anyone else in Changi was involved in the sabotage, or with the raid that led to serious repercussions on 10 October—"the double tenth", as it happened on the tenth day of the tenth month, which is the National Day of the Republic of China. On 28 September, Scott received a message from one of his contacts in the city, telling him that on the previous morning six Japanese ships had been blown up in Singapore Harbour (now Keppel Harbour). This was the first major sabotage since the Japanese had captured the island. The loss of ships in such an important place was an enormous blow to Japanese prestige. Scott and his fellow internees supposed that the saboteurs must have been Chinese guerrillas who had slipped across the straits from their base in Malaya. Sumida, however, believed that Scott and his associates had planned the operation from Changi Prison.
Operation Jaywick
The attack on Singapore Harbour was codenamed Operation Jaywick, the brand name of a popular lavatory deodoriser, and had nothing to do with guerrillas or fifth columnists. It had been carried out by Lieutenant Colonel Ivan Lyon from Z Special Unit, a group of Anglo-Australian commandos who had sailed from Western Australia to Singapore in an old Japanese fishing boat, the Krait, named after a Malayan snake. Once within striking distance of the harbour, the commandos took to folboats (folding canoes), and paddled into the docks under cover of night. Using limpet mines, they sank six Japanese ships of 2,000–5,000 tons, including several tankers, and then slipped away to their rendezvous with the Krait, finally returning successfully to Australia. (The Krait is now preserved and on display at the Australian National Maritime Museum in Sydney.) The Japanese could not conceive that a force could penetrate their lines of defence and have the audacity to attack their shipping. They therefore concluded that it must have been an internal operation, carried out by Chinese guerrillas organised from Changi Prison.