In 1943, the Japanese began several projects to create efficient troop and equipment transport routes between Thailand and Myanmar in support of their planned attacks on Imphal and Kohima. In addition to the well-known Death Railway through Kanchanaburi, one of these projects was the improvement of the existing road from Chiang Mai to Pai and the patchwork of trails on to Mae Hong Son. The method of crossing the Pai River about 10 km south-east of the City of Pai is not, at present, verifiable. A bridge at that site was erected after the war and erroneously named the "World War II Memorial Bridge". It was apparently erected (and subsequently twice extended) in the course of road improvement projects by the Thai government. The Japanese attempt to develop a road connection between Chiang Mai to Pai and on to Mae Hong Son was abandoned in early 1944 when it became evident that the improvements could not be completed in time for the scheduled attack on Imphal. The uncompleted road did serve as an avenue of retreat for the Japanese after their disastrous defeat at Imphal and Kohima.