Thanks for the speculations. Interesting. The following image shows where that rig was being used. These weddings are first a private ceremony, then a formal procession through the main temple grounds, then a retreat to side areas for staged group shots. This rig was in the latter, so it was being used for carefully staged and static stills. Just out of frame are about 20 people from the wedding party, waiting their turn.
I was in Japan for the wedding of a friend. But that one was a "western style", held in a hotel that caters to weddings. The hotel (Westin) had a special wedding chapel and a special photography studio.
After the ceremony, family and close friends were herded into the studio for group shots. I counted 8 strobes, permanently mounted to the ceiling and walls. There were 5 cameras on tripods, a mix of Nikon and Canon, all digital.
My friend, the bride, told me earlier that they could have bought a new car for what the photography was costing. I don't think she was joking. Before the wedding, she showed me a photo album of her and the husband. All "wedding" shots, but taken a month before the actual wedding. The quality was outstanding. During the actual wedding and reception party there were 3 shooters plus assistants. The whole affair lasted 7 hours.