Iwakuni Castle is classified as a mountain castle (its layout: Renkakushiki), and is located in Yamaguchi Prefecture. During the pre-modern age, it found itself within the borders of Suō Province. It is associated with the Kikkawa clan. Dates in use: 1601 - 1615.

Iwakuni existed as a fully-fledged castle for just 15 years. The Shogunate issued an edict in 1615 limiting this province (and most others) to just one castle. The result of this saw the towers, gates & defensive enclosures at the top of the mountain abandoned. The surrounding lands continued to be administered from the offices at the base of the mountain.

The story of Iwakuni castle's Tenshu of is an interesting one. The main tower, though concrete, was based on the original designs. Interestingly, it was built 30 metres from its original location, on the southern edge of the main enclosure, so as it can be viewed from the city below.

At the base of the mountain and spanning the river is a fascinating bridge called Kintaikyo. It was originally built in 1673 & continues to have sections rebuilt on a regular basis. Only samurai were permitted to cross it but now paying a small fee will qualify you.

Timeline

1601	The Kikkawa clan were transferred here and started construction of the castle.
1602	The main tower was completed. Oddly, it was topped with a thatched roof. Most unusual for Tenshus of this period.
1607	The buildings, walls & moats located at the base of the mountain were completed.
1608	The main tower's supporting buildings of the Honmaru were completed.
1615	The Tokugawa Shogunate ordered the castle be abandoned. Thereafter, administration of the fief was undertaken at the building complex at the base of the mountain.
1962	The main tower was reconstructed.