The couples dress up in front of their friends and families, vow never to see each other again, and then smash a ring with a hammer. The idea is to emulate the formality of a traditional wedding in the hopes of increasing the acceptability of the once taboo practice. With the divorce rate in Japan continuing to climb there are now companies that specialize in providing divorce ceremonies like these.
There's more information on Japanese divorce ceremonies here, including separate carriage rides and the most awkward receptions ever.
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