Ohori Park was built as a defensive moat for the magnificent Fukuoka Castle; the home castle of the Kuroda clan (黒田氏). In fact, the land where both the park and the castle ruins was awarded to the Kuroda clan (黒田氏) by none other than Tokugawa Ieyasu (徳川家康), one of the three unifiers of Japan. This award was for the contribution of the Kuroda clan as they sided with the Tokugawa clan (徳川氏) in the famed Battle of Sekigahara (関ヶ原の戦い) to defeat the enemies and even killed a famed general known as Shima Sakon (島左近).
When the lord of the Kuroda clan, Kuroda Nagamasa (黒田長政) commenced the construction of Fukuoka castle in AD 1601, he also ordered the construction of the moat. For a fun fact, the area was originally a marshland called Kusagae (草ヶ江) which was connected with the Hakata Bay. Upon construction of the moat, Kuroda Nagamasa changed the name of the area into Ohori (大濠); literally translates as a large moat.
Fast forward few centuries later, the local council commenced a construction plan in 1925 to transform the area into a park upon receiving proposals from the locals. The design of the park derived its inspiration from the West Lake of Hangzhou, China; incorporating elements such as a scenic pond together with gardens. Eventually, the park was opened in 1929 and it became a beloved hang out spot among locals; simply for its scenic beauty.