And the sad thing was that the returning flight (to HK) was early in the morning... yes, mo barn fat... we only managed to find those flights by then... the offer was very limited...
Nevertheless, the trip to Kyushu was great to my family. We like there a lot, and I particularly love Kagoshima :)
Kokura is a very nice small town. Kokura-jo is within walkable distance from the train station if you don't drive. Next to Kokura-jo is a mall called Riverwalk Kitakyushu which is very big and trendy. You may also consider to spend the morning in a small port nearby, Mojiko, and even travelling to Honshu opposite (just by boat about 15 min or so) to browse around Shimonoseki (with an aquarium and a small fish market next to the waterfront). In the afternoon, you return to Kokura and then go back to Fukuoka at night. Seems a bit rush but actually not, that's what we did last time upon visiting Kokura.
Anyway, search "Kokura" on the internet and you can discover much more! (including its history during WWII, from which you may learn more about "fate".)