Kintai bridge(Kintai-kyo. Kyo means bridge in Japanese) is located in outskirt of Iwakuni city, Yamaguchi prefecture, close to Shin-Iwakuni station of Sanyo shinkasen line. Iwakuni castle is also nearby. It is a historical wooden arch bridge, spanning over Nishiki river. Natural treasure since 1922.
Iwakuni city has two significant tourist attractions. Kintaikyo and Iwakuni castle.
However, I consider less popular than other cities in Chugoku region, western Honshu.
Although it is 42 minutes by rapid train or 52 minutes by local train from Hiroshima station, most of the tourists visit Atomic Bomb Dome and Miyajima(Itsukushima Shrine) when they go to Hiroshima and do not consider to visit Kintaikyo and Iwakuni castle.
Yamaguchi prefecture is also a very attractive place. It used to be two provinces, Nagato and Suou which merged in late 19th century to become Yamaguchi prefecture. Hagi city was the castle town or seat of Choshu han(Domain) of Mouri Clan, the one of the largest clans during Edo era. Small island called Ganryujima, which is lying very close from Shimonoseki city is the place where two all time strongest samurais, Musashi Miyamoto and Kojiro Sasaki fought each other. Then, another place is Akiyoshi-do(Shuho-do) karst caves, which is the Natural monument of Japan.
Then, when you visit Yamaguchi prefecture, especially the biggest city Shinomoseki, you should try FUGU, the pufferfish.