The collapse of K-1
The organisation that built modern kickboxing ran out of money, and the sport spent two years finding out whether it could survive its own founder.
K-1's original organisation collapsed financially around 2011–2012. Fighters went unpaid, events were cancelled, and the promotion that had defined the sport for eighteen years effectively stopped operating.
The cause was structural rather than sporting. K-1 had been built on Japanese television money and a business model that depended on continual expansion; when the broadcast revenue contracted and legal difficulties accumulated around its leadership, there was no smaller version of the operation to fall back to. The heavyweight roster — the most expensive part — was also the least replaceable.
What happened next is the interesting part. The sport did not disappear with the promotion. The ruleset had already spread, the fighters were already trained under it, and the European scene had its own infrastructure in It's Showtime and the Dutch gyms. Within a year GLORY had consolidated much of that into a single brand, and within two the sport had a functioning global promotion again.
The brand itself was later revived as a Japanese domestic promotion, where Takeru became the defining figure. But the K-1 that mattered internationally ended in 2012.