The first phase of the Eight-Eight plan began in 1910, when the Diet of Japan authorized the construction of one battleship (Fusō) and four battlecruisers of the Kongō class. Designed by British naval architect George Thurston, the first of these battlecruisers (Kongō) was constructed in Britain by Vickers, while the remaining three were constructed in Japan. Armed with eight guns and with a top speed of , they were the most advanced capital ships of their time. At the height of the First World War, an additional four battlecruisers of the Amagi class were ordered. The ships would have had a main battery of ten guns, but none were ever completed as battlecruisers, as the Washington Naval Treaty limited the size of the navies of Japan, Britain and the United States. Before the Second World