At the request of General Estienne and on the basis of previous studies worked out by Renault, Schneider, FAMH, FCM, and Delaunay-Belleville, a new battle tank was developed under the code designation of "Tractor 30". In 1929-30, three pilot models were built by Renault and FCM. These later became designated Char B. These three pilot models were extensively reworked and modified for tests. The first one, reengined and uparmored became the early prototype for the B1-ter in 1937. The Char B1 was the production version of the Char B. Production began in 1935. Only a small number were built before construction changed to the more powerful B1-bis. The B1-bis was the main battle tank of the French army in 1940. Considered one of the most powerful and advanced tanks in the world, it was hampered only by it's low speed and cost of production. The B1-ter did not go beyond protype stage. Studies started in 1935. Had the B1-bis been better employed, it would have easily defeated any invading German tank in 1940.
