Japan Castle Atlas
A few things worth knowing before you visit — they change what you see.
The tall tower you see in photos is the tenshu (main keep) — only one part of a castle. A castle is a whole defensive system of kuruwa (baileys, or walled enclosures) divided by moats and stone walls. Many castles never had a keep, and many have lost theirs. When you visit, look beyond the keep: the route from the gate to the top, the width of the moats, the height of the walls.
A keep built before 1868 that still stands is called an original keep (genzon tenshu). Most keeps were demolished in the Meiji era or destroyed in war, and many were rebuilt later. A keep rebuilt in timber from plans and photographs is a 'wooden restoration'; one whose outside follows the records but whose inside is modern is an 'exterior restoration'; a 20th-century rebuild that may differ in shape or position is a 'reconstruction'; and a keep built where none ever stood is a 'mock keep'. For each castle, this atlas shows which applies, with sources.
Even when no buildings remain, the castle's shape is still in the ground. Flattened areas are kuruwa (baileys). A deep cut across a ridge is a horikiri (trench cut); a trench running down a slope is a tatebori (vertical moat); a raised bank of earth is a dorui (earthen rampart). An entrance that turns at a right angle is a koguchi, designed to break an attacker's momentum. Look at the site plan (nawabari-zu) on the information board before you walk, and the logic of attack and defence starts to appear.
Stairs inside original keeps are very steep — some are close to ladders. Keep your bags light so you can use both hands. At many keeps you take off your shoes at the entrance and carry them in a bag. Mountain castles are reached on unpaved trails that get slippery after rain: bring proper shoes and water. How much of a site is accessible by wheelchair or stroller varies; check the visiting section for each castle.
Many Japanese cities grew out of castle towns, so quite a few castles are close to a railway station. Each castle page lists the nearest station, walking time and how much climbing is involved — only where we could confirm them. Buses to mountain castles and rural sites can be infrequent: check the return times before you set out.
Photography may be prohibited in parts of keeps and museums, and flash or tripods are often not allowed. Climbing stone walls or crossing fences is dangerous and damages the remains. Some castle sites include private land or closed areas — follow local signs, and do not enter places marked 'private' or 'partly open' in this atlas. Flying drones requires permission at most castles.
