 During the 1930s , both ships underwent a series of modernizations and reconstructions . Fusō underwent her modernization in two phases ( 1930 – 33 , 1937 – 41 ) , while Yamashiro was reconstructed from 1930 to 1935 . The modernization increased their armor , replaced and upgraded their machinery , and rebuilt their superstructures into the distinctive pagoda mast style . Despite the expensive reconstructions , both vessels were considered obsolescent by the eve of World War II , and neither saw significant action in the early years of the war . Fusō served as a troop transport in 1943 , while Yamashiro was relegated to training duty in the Inland Sea . Both underwent upgrades to their anti @-@ aircraft suite in 1944 before transferring to Singapore in August 1944 . 
