on the weekend i went to the painters and meet a old bloke there who told me that the name datsun started at nissan motors because in world war 2 there was a japenese leader in the army by the name of nissan and he would kill people for looking at him. can anyone tell me weather this is true

that old man deserves an "a" for creativity

but if you really want to know how this came about,
grab a sandwich and read this excellent article:

What's in a Name? by Dan Banks

Also see our club's own mini-history: Nissan History as it relates to Datsun 1200Quote:

That old bloke is the one that told me that Ferrari is vietnamesse company whose owner married an italian girl with Ferrari as a surname..............

and i found this on the early datsun homepage
1912 - First DAT built.
- Kwaishinsha Motor Car Works founded.
1913 - Second DAT built.
- Production begins.
1915 - DAT 31.
1916 - DAT 41.
1919 - Formation of Jitsuyo Jidosha Seizo.
1920 - American designer William R. Gorham starts work at
Jitsuyo Jidosha Seizo.
- First Gorham 3 wheeler built.
- 3 wheeler production begins.
- DAT truck.
1921 - Gorham's 4 wheeler, called the Lila, began production.
- Lila Light Truck.
1926 - DAT Automobile Manufacturing Co. and Jitsuyo
Jidosha Seizo merger.
- DAT car production stops, truck production continues.
Lila car production continues.
1931 - DAT becomes part of Tobata Imono group.
1932 - Cars now known as DATSON. (with an O )
- Datson 91. (Phaeton)
- Cars now known as DATSUN. (with a U )
- Datsun 91. (same as Datson 91)
- Datsun Roadster.
- Datsun 1/2 ton truck.
1933 - Datsun Type 12.
- Tobata Imono group reorganised. Jidosha Seizo
Company Ltd. formed to build Datsun cars and trucks.
- Company name changed to Nissan Motor Company
Ltd.
1934 - Datsun Type 13. (also called Datsun Type 91)
1935 - Datsun Type 15.
- Yokahama plant begins operations.
- Datsun Roadstar.
- Datsun Coupe.
- First exports begin.
1936 - Datsun 15T Truck.
1937 - Datsun Type 16.
- Nissan 70. (Nissan Six). The Nissan 70 was a
Graham-Paige built under licence.
- Nissan Bus 98 A-T
1938 - Nissan 5 ton Truck.
- Datsun Type 17.
- Passenger car production ceases, only truck production
continues.
1939 - Datsun Delivery Van.
- World War 2 begins.
1940 - Nissan 50. (Nissan Six)
1942 - Nissan Military truck.
- Military aircraft engine production begins.
- U.S. Occupation forces take over Nissan plants after
the end of World War 2.
1947 - First post-war Datsun car produced.
- Datsun DA.
- Nissan Pick-up.
1949 - Nissan Truck 180.
1951 - Datsun DB.
- Datsun Pickup 1121
1952 - Nissan signs licence agreement with Austin of England.
- Datsun DC-3.
- Nissan Patrol.
1953 - Datsun Pickup 6147.
1954 - Nissan Carrier.
1955 - Datsun/Austin A40 Somerset.
- U.S.Occupation forces return ownership to Nissan.
- Production of UD Nissan Diesel trucks begins.
- Datsun A110.
- Datsun 120 Pickup.
1956 - Datsun/Austin A50 Cambridge.
1957 - Datsun 210. (Datsun 1000)
- Nissan Junior B40.
- Datsun 220 Pickup.
1958 - A Datsun 210 wins the Mobilgas around Australia
rally.
- Datsun Cablight
1959 - Datsun Sport S211.
- Datsun Bluebird 310.
1960 - Nissan Cedric 30.
- Datsun Fairlady SP212.
1961 - Datsun Bluebird 311.
- Datsun Fairlady SP213.
1962 - Datsun Bluebird 312.
- Datsun Fairlady 1500 SP310.
- Nissan Cedric 31.
1963 - New Oppama factory opens.
1964 - Datsun Bluebird 410.
1965 - Nissan Cedric 130.
- Cony taken over by Nissan Motor Co.
- Nissan Silvia CSP311.
- Datsun Fairlady 1600 SP311.
- Datsun 520 Pickup.
- Nissan President V8.
- New Zama factory opens.
1966 - Merger with Prince Motor Company.
- Datsun Sunny. (Datsun 1000)
1967 - Datsun Fairlady 2000 SR311.
- Datsun Bluebird 510.
- Nissan/Prince R380 sports prototype breaks seven
world speed records at Fuji Speedway.
1968 - Nissan Laurel. (Datsun 1800)
- Nissan Skyline.
1969 - Datsun Fairlady Z. (Datsun 240Z)

does this answer your question