I took my bicycle on the night ferry from Matsuyama to Kokura on a hot weekend in July for a day of sightseeing and eating. Loading starts at 9:00, and the ferry departs at 9:55. The parking staff took good care of my bicycle, wrapping it in blankets and strapping it to a bulkhead. The ferry has a well-appointed bathroom. Before the boat gets underway, everybody rushes in there to avoid the rush. Wait an hour, and you have it to yourself.
After my bath, I went on deck to enjoy the night views of the inland sea and the other ships. It was surprisingly cool on deck, and it was very relaxing to watch the lights of the port recede and other boats drifting past. Some benches would have been good to sit on instead of standing at the rail.
The lounge area offers very reasonably priced food and drinks and it's convivial. I had a good chat with two groups of travelers who were relaxing over drinks. In the tatami seating area, a group of Japanese motorcycle 'outlaws' were making a good deal of harmless noise.
Sleeping accommodation is available in three grades – a big communal floor space with a thin futon, blanket and plastic pillow, rooms with bunk beds, and twin bedrooms. I was in 'steerage' on the floor. When I made my way quietly between the sleeping people to my assigned space on the floor, I found a little girl in my space, who had rolled away from her dad. Fortunately there were some empty spaces. The plastic pillows aren't very comfortable so I used a rolled up shirt. I spent a fairly rough night, and when the ship arrived in port at 5 am, I was glad to get up.
Disembarking was quick and easy. I had fun photographing the bikers as they roared off the boat on their assortment of Harleys, side cars and three-wheelers.
At Kokura, I visited the castle, the 'retro' area at Mojiko, the railway museum, and the grotty but atmospheric market at Tanga. The early morning light was fantastic for taking photos, especially with a full moon still high in the sky.
I would recommend the ferry for travel between Kyushu and Shikoku. The facilities onboard are clean, and the staff are pleasant. Accommodation onboard is air conditioned to a comfortable temperature. Sleeping on the boat saves you the cost of staying in a hotel, and traveling while you sleep gives you more time at your destination.
Kokura and Matsuyama are both beautiful historic cities with lots to see and do. The possibilities are in no way exhausted in one day, even if you happen to be. On the way back, I enjoyed a refreshing, coma-like sleep.