Tenshu, whose rate of decrease in roof size became low and the Boro part of which became low in function as watchtower, were, in many cases, constructed after the Battle of Sekigahara and these are regarded as later period ones; examples include the Himeji-jo Castle keep.
姫路城天守などの関ヶ原の戦い以降に造られたものに多く、屋根の逓減率が小さくなり、望楼部分の物見の要素が低くなったものを後期という。