It was built by Niwa Ujikiyo in 1538 (Tenbun 7). When Oda Nobunaga and Tokugawa Ieyasu formed an alliance, the Niwa clan allied with Oda Nobunaga, and after Nobunaga's death, they allied with Tokugawa Ieyasu.
During the Battle of Komaki and Nagakute in 1543 (Tensho 12), Niwa Ujitsugu, the head of the clan, headed for Komakiyama Castle, Ieyasu's main camp, while his younger brother Niwa Ujishige defended Iwasaki Castle. As the battle reached a stalemate, Hideyoshi's subordinate Ikeda Tsuneoki led an army through Iwasaki Castle and advanced toward Ieyasu's main castle, Okazaki Castle in Mikawa Province, but Ujishige met them with over 300 castle soldiers and was killed in battle.
Currently, there is a mock castle tower, and the dry moat and earthen ramparts remain.
During the Battle of Komaki and Nagakute, the castle lord, Niwa, who sided with Ieyasu, attempted to block the march of Hashiba's forces towards Okazaki from that direction, but 300 men fought against 7,000 and the castle fell.
However, this time-wasting opportunity allowed Ieyasu's main force to catch up, which had an impact on the subsequent battle.
The castle tower is a replica, but it gives off a more castle-like feel and is well worth seeing.
There are also quite a few remains of the real thing, but the area around the main castle was not very large, so you can see everything in a relatively short amount of time.
There is free parking, and you can also enter the observation tower in the replica castle tower and the historical museum for free.
Approaching Iwasaki Castle from the parking lot, you'll find a promenade that leads down to the dry moat, a suikinkutsu water fountain in the Ninomaru horse-shed, and remnants of earthworks and wells.
From the other side, a large stone monument bearing "Iwasaki Castle" appears in the background, and a short staircase leads to the impressive gate and castle tower.
Once through the gate, you'll find a masugata (square-shaped enclosure) that offers ample opportunity for attack from all sides. It's a small castle, but packed with fun elements. 😊
Historically, according to documents from the Iwasaki Castle Historical Museum, the valiant efforts of 16-year-old castle lord Niwa Ujishige in the Battle of Komaki and Nagakute, between Hashiba Hideyoshi (later Toyotomi Hideyoshi) and the allied forces of Oda Nobukatsu and Tokugawa Ieyasu, are said to have paved the way for the Tokugawa's victory. (Politically, Nobukatsu was manipulated by Hideyoshi, so it's hard to say who won...)
You can learn about the history of Iwasaki Castle and the surrounding area at the Iwasaki Castle Historical Memorial Museum and inside the castle.
While other places would likely charge around 500 yen for admission, it's free! 😳
What's more, while the castle seal at other castles would cost over 300 yen, it was only 200 yen at Iwasaki Castle.
What a very reasonable castle!
It's a well-maintained castle.
It's free.
The castle ruins have been turned into a park, and there is a memorial hall and a restored castle tower, which are well worth seeing. The remains of the dry moat and turrets are still in good condition, so it was a fun place to look around.
