A broadcaster’s lineup creates a halfpipe cliffhanger in Japan.

It was Ayumu Hirano’s last ride, and the final run of the men’s halfpipe finals at the Beijing Olympics on Friday. Shaun White, the American snowboarder competing in his last Olympic Games, had already fallen, leaving a spot for his successor on the top step of the medals podium.

Hirano, of Japan, was in position to win, and his fans — many of whom were at home for Japan’s National Foundation Day — were glued to the television, waiting for the halfpipe cliffhanger.

Then the television signal dropped, replaced on screens across Japan by a notice that read simply: “Subchannel. Guidance on how to shift. Please have a remote control.”

As most of the nation fumbled with its televisions, Hirano completed a nearly flawless run with spectacular jumps that assured him the gold medal. The response on social media was loud and angry.

So many people had missed witnessing the significant moment that #Subchannel was trending on Twitter, with 42,000 tweets at one point. Most of them questioned why the Japanese broadcaster NHK hadn’t waited until after the competition to make the channel switch.

An NHK spokesman said that the broadcaster had made the schedule in advance, and that it had called for shifting the live Olympics coverage to the subchannel so that weather and news could start at 11:54 in the network’s main channel.