This heavy turret guards the southwest corner of the castle. It has a unique (and deliberately deceptive) feature: though you'd never be able to tell by looking at it from the outside, the structure actually has five separate floors, making it a miniature castle in and of itself.
The turret is mainly compsed of pine wood. As many at 46,000 tiles in total are used to cover the roof.
This is another one of the three level, five-story turrets that surround the castle's main tower. Back in its heyday, there were six such towers.
The Uto Trrret is one of the only remaining structures on the grounds of Kumamoto Castle that dates back to its original construction in the late 1600's. It unerwent repair in 1985 and was reopened to the public in October, 1989.
Kumamoto Castle is considered to be one of the three premier castles in all of Japan (along with Himeji and Matsumoto). This is due, in large part, to the sheer size of the castle, as well as the unparalleled masonry work on display.
There's a museum inside the castle's main keep, and I believe these kanji characters spell out the names of various donors.
Honmaru Goten Palace
One of the many unique features of Kumamoto castle is this, the recreation of the palace and living quaters of the feudal lord. The original building was destroyed during the Seinan Civil war in 1877.
As is the case with most other structures on the grounds of Kumamoto Castle, the original main keep burned to the ground during a siege leading up to the Seinan Civil War. However, great care was taken during its reconstruction in 1960 to ensure that the building we see today closely resembles the original.
Though its origins as an area of simple fortifications date all the way back to the late 1400's, the castle we know today truely started to take shape in 1601. It took seven years to complete construction.
Uto Turret (foreground) and Main Keep (background) as the sun begins to set.