Comedians laugh at their own jokes. It’s part of the gig, given how a performer’s laughter eases an audience—infects them, if you will—and spreads through them, like ripples formed by tossing a stone into a ticklish lake. This idea is tested by the strangely compelling Japanese reality competition, Documental, the first two seasons of which are now on Amazon Prime Video. Ten comedians, of varying style and popularity, are locked in a room for 6 hours, each trying to make the others crack up while keeping their own composure intact. They who laugh are eliminated.

It sounds straightforward enough, but this is a Japanese show and, characteristically, nothing turns out as expected. Created and hosted by renowned comedian Hitoshi Matsumoto, the invitations for Documental are handed out sinisterly, as if chosen comedians are being given envelopes containing six orange pips and being cursed, not commended. It is also unusual that contestants must stake their own money—the prize is ¥11 million, with each player (plus Matsumoto himself) bringing ¥1 million to the table, making it feel more like a card game than a reality competition: a veritable World Series of Poker-Faces.

Before combat begins, there is a solemness to the proceedings. “People don’t laugh at me but comedians find me funny," reveals a competitor, preparing to take on the perils of the room. “Even her poker face is funny," Matsumoto says about one player, while another is described as a “mood maker who brings a wild energy to the room". The host is dismissive about a less famous player pitted against senior comedians, saying it would be like a man trying to tickle hard-hitting professional wrestlers.

This talk of seniority and strategy made me picture a scene of comedic virtuosity, one where highly-skilled artistes would launch forth with jokes too sharp and insightful to not be laughed at, humour so finely polished it would be irresistible. I first began to suspect my expectations might be off when one enthused young competitor said—in all seriousness—that one of his key strategies was going to be “to show the butt-hole". Right. This isn’t quite going to be a competitive edition of A Bit Of Fry And Laurie, then.

The comedians critique each other on the spot, talking about timing and technique. “That sure was a great face," they say about one weirdly eerie face pulled by a veteran. “It’s the face of a classic comedian." It may be, but that isn’t what they laugh at. That’s the thing, anything can be a trigger. And while the outlandish (and often vulgar) triggers themselves might not be our individual cups of tea—one competitor’s entire shtick is to furiously yell out his own name—it is delightful to watch these comedians bust out laughing and lose their place.

On the British sitcom Coupling (also streaming on Amazon Prime), there is a citation of a phenomenon called the “giggle loop", an involuntary impulse to laugh during a most inopportune moment, causing you to swallow the laughter and suffocate it within, which of course amplifies it, eventually causing a most inappropriately timed and loud laugh. “It’s an enormous laugh. Let this bastard out and you’ve got whiplash," warns the show’s resident know-it-some, Jeff Murdock.

The Documental set is made up of giggle-loop landmines. The comedians make faces, put their testicles inside the pipe of a vacuum cleaner, make their heads bleed, fool around with props of all types. It is so puerile, so unashamedly stupid, that watching it frequently feels dirty. This, then, is less about comic sophistry than about surprise. Elaborate costume-based routines fail to evoke a laugh, while a fortuitously timed stutter gets a professional to break down and lose his place in the competition.

“That stutter was incredible," admits the comedian on his way out, and Matsumoto must then deliberate which comedian should get the point for his exit: the one who stuttered, or the one who first reacted to the stutter before the laugh-er, thereby evoking the laugh. It all sounds nuts but once you’ve waded in 20 minutes deep, Documental is difficult to look away from. By not being allowing to laugh, comedians are forced into an unnatural style of performance. “They have the same problem as boxers," Matsumoto explains. “Whenever they make an attack, their guard drops."

Think, for a moment, about the great Rowan Atkinson, who played the slapstick wordlessness of Mr. Bean as elegantly as he handled the immaculately enunciated historical sarcasm of Blackadder. The humour on this show may feel primitive, but laughter surpasses judgement. Documental serves as a reminder of how it doesn’t matter where exactly a laugh comes from, as long as it arrives with unstoppable force. Laughter may be the best medicine, but one man’s tonic is another man’s pill.

Stream of Stories is a column on what to watch online. Raja Sen is a film critic and the author of The Best Baker In The World (2017), a children’s adaptation of The Godfather.

He tweets at @rajasen