Nagoya Castle was built in the beginning of the Edo Period as the seat of one of the three branches of the ruling Tokugawa family, the Owari branch. As such, it was one of the largest castles in the country, and the castle town around it ultimately grew to become Japan's fourth largest city.
Most castle buildings were destroyed in the air raids of 1945, including the castle keep and the palace buildings. The current ferro-concrete reconstruction of the castle keep dates from 1959 and contains a modern museum with exhibits about the castle's history. The park surrounding the castle keep features two circles of moats and impressive walls with corner turrets. It becomes an attractive hanami spot during the cherry blossom season which usually peaks in late March or early April.
From Nagoya Station, take the Higashiyama Subway Line to Sakae Station (5 minutes) and change to the Meijo Subway Line to Shiyakusho Station (2 minutes). The total one way journey takes about ten minutes and costs 240 yen. From the nearest exit, it is a three minute walk to the castle's east gate.
Alternatively, the castle's main gate can be reached from Nagoya Station by the Meguru tourist loop bus in about 25 minutes. The fare is 210 yen per ride or 500 yen for a day pass.
Comprehensive List of Major Castles in Japan