'Chess' was a British special forces raid on the village of Ambleteuse on the north coast of German-occupied France (27/28 July 1941).
The undertaking was a reconnaissance mission that served as a operational training exercise for the 16 men of No. 12 Commando, under the command of 2nd Lieutenant Philip Pinkney, landed and later extracted by an assault landing craft, which met a small force of covering motor torpedoes boats some 10 miles (16 km) to the south-east of Dover as it returned home. The operation took no prisoners and suffered no casualties during its one hour ashore.
Although the raid was not in itself a great success, it did serve to prove that there was merit in small as well as large commando raids, and as a result 'Acid Drop' and 'Cartoon' were planned as successor efforts, although the latter was cancelled.