Bridge on the River Kwai, The
The Bridge on the River Kwai is the 1957 World War II film directed by David Lean and stars William Holden, Jack Hawkins, and Alec Guinness. The film is considered by many to be one of the greatest war movies ever made. A huge box office hit upon its release, the film was nominated for eight Academy Awards and won seven including Best Picture, Best Director (David Lean) and Best Actor (Alec Guinness). A similar premise involving the infamous "Death Railway" was seen in the unrelated 1989 film Return from the River Kwai.
The following weapons were used in the film The Bridge on the River Kwai:
Lee Enfield Mk III*
What is interesting to note that in the film, the Japanese guards do not use Arisaka rifles. Instead they are seen using Lee Enfield Mk III* rifles! The movie was filmed on Sri Lanka (Ceylon in 1957) and had been a British colony until just a few years earlier. The reality is that the production company was able to get British firearms with ease and the thinking probably was nobody would really notice or pay attention. But for the sake of the story, it can be argued that the Japanese equipped the guards with British firearms because after the fall of Singapore in the spring of 1942 there was an abundance of British equipment. Incidentally the British used American firearms such as Thompson smg's as well. All the warring nations equipped the P.O.W. guards with second hand equipment. It was difficult enough keeping their front line troops equipped so far away from Japan. So some thrifty Japanese commanding officer decided to equip the guards with British equipment. They wouldn't be in much action and the need for constant re-supply would not be a concern.
Lee Enfield No.4
Some of the Japanese soldiers are also seen with Lee-Enfield No.4 rifles.
Thompson Submachine Gun
In the opening credits when the British prisoners are marching from the railhead to the camp several of the Japanese guards appear to be equipped with Thompson M1928A1 Submachine Guns! See above for the logical explantion and my explanation to explain such a strange situation in the story.
Sten Mk. II
Canadian Sten Mk II submachine guns are used by the Commando team tasked with destroying the bridge.
The Japanese guards use a couple different versions of the Vickers Machine Gun. Once again see the Lee Enfield discussion above for an explanation.
Ordnance SBML 2 inch Mortar
What appears to be a British Ordnance SBML 2 inch Mortar is used by Major Warden (Jack Hawkins) during the attack on the bridge. The exact model of the mortar is hard to identify but it matches a long-barreled infantry version rather than a shortened paratrooper version.