High-tech 'sassen' duels are an active otaku's dream


Part fencing, part kendo and part freestyle swordfighting, sassen combines multiple disciplines into an undeniably engaging package. | OWEN ZIEGLER
BY OWEN ZIEGLER
STAFF WRITER

Mar 25, 2023

It’s an otherwise normal October night in the Akihabara district in Tokyo as tourists and locals alike plod along the glowing neon streets. Young women in maid outfits beckon half-heartedly to men ambling in and out of ramen shops, PC parts suppliers and anime retailers.

Several floors above? It’s fight after fight to the death.

Figuratively speaking, of course — combatants grasp not steel katanas but carbon fiber batons laden with accelerometers and other sensors, all wrapped in foam to soften the inevitable blows. They swing not to maim or kill but for points, though there’s still a palpable, primal aggression in the air when two competitors face off.

From more than 2,000 entrants competing at satellite preliminaries across the country, a few dozen had won the right to come to Akihabara for the tournament finals of “sassen” and to vie for a ¥100,000 ($767) prize — a decent purse but somehow less motivating than the energy in the air I sensed that day.


From more than 2,000 entrants, only a few dozen advanced to Sassen’s national finals in Akihabara in October. | OWEN ZIEGLER
A mix of traditional kendo, modern fencing and freestyle sports chanbara (a multidisciplinary combat sport that simulates historical Japanese melee combat), sassen can be difficult to define. First begun in 2016, the sport still has a nascent community, the technology underpinning it isn’t without its occasional hiccups, and the name itself is a created word combining inspiration from satsuzen, a Japanese word meaning “wind-breaking” or “dashing” speed, plus techniques used by famed Sengoku Period (1482-1573) swordsman Miyamoto Musashi.

That all might be secondary to a much more salient point, one that snaps into focus as soon as you brandish your electronic sword and stand across a likewise armed opponent: sassen scratches an otaku-shaped itch like few other pursuits.

Rules of war
The basic rules of sassen are simple — the first to score two hits anywhere except their opponent’s head in a 60-second match wins. But pick up a “sassen-to” (the company’s native nomenclature for its high-tech swords) and you quickly learn that this is no simple game of high-tech tag.

For one, competitors are discouraged from swinging wildly. A dedicated official keeps track of the five total swings per match allotted to each contestant. Once those are used up, all you can do is evade your opponent until time runs out. The illuminated batons are also configured so only one section registers as the cutting portion of the would-be blade. Swinging wildly at your opponent may land a hit, but if contact is only with the deadened section of the baton, the embedded sensors won’t register a successful strike. Forget where your edge really is and the decisive blow you think you’ve landed might be the opening your rival is waiting for.


Strength is less important in a sassen duel than speed, positioning and accuracy. | OWEN ZIEGLER
“Each baton is only about 300 grams and 65 centimeters long,” says Seita Sukisaki, chief technical and financial officer at Sassen, who spearheaded the Bluetooth-supported technology underpinning the equipment. “But the carbon sleeve inside has about ¥200,000 (about $1,520) worth of electronics.”

All that alone would be a solid foundation for thrilling duels reminiscent of bygone warriors, but sassen goes one step further: If a combatant lands a successful blow (signaled by a slashing sound played over the PA system), the other has an infinitesimal window, no more than a few tenths of a second, to land a counterstrike. If both combatants effectively cut each other down in the same breath, the two strikes cancel each other out, a sharp ringing sound blares instead of a slash and the breathless match continues.

Over the course of the afternoon, this game mechanic shows itself time and again to be a defining element of sassen. If one competitor outmatches another on footspeed, the other times a lifesaving counterblow instead. Conversely, if an overcommitment to an opening attack leaves a competitor defenseless, presence of mind and a quick wrist keeps them alive for one more moment and one more swing.

“Sassen is meant to be a martial art but one where there’s no real threat of injury or harm,” says Ryoma Motomura, creator of sassen and founder of parent company Satsuzen, who also served as emcee, play-by-play commentator and instant replay judge for close calls during the October competition. “I come from a family of karate-ka (karate athletes), so I know how difficult training and participating in traditional martial arts can be. Sassen, on the other hand, is for everyone — young and old, veterans and newcomers.”


Sassen founder Ryuma Motomura serves as emcee, play-by-play commentator and instant replay judge for some sassen sessions. | OWEN ZIEGLER
Suffering a blow from one of the batons doesn’t feel good, per se, but anyone who managed to walk away from a swiftly thrown dodgeball back in elementary school gym class can also bounce back from even the stiffest of strikes during a sassen match. According to Motomura, sassen is also priced much more invitingly for newcomers than other traditional martial arts. A beginner’s kendo set might run around ¥20,000 to ¥30,000, but one-off trial passes for drop-in sassen sessions go for around ¥1,000 to ¥2,000 with nothing other than your own athletic clothing required.

“Sassen’s soul is a martial art,” says Motomura. “But it’s a much more modern approach — and that’s to do with more than just the technology.”

Triumph and defeat
Astride the blue and black mats, two swordsmen bounce around each other on the balls of their feet. One might feint with their baton to the left; the other might shift his momentum to the right. A swing and a miss draws a few gasps from the modest crowd watching the tournament’s championship match — and when Rikitake Yuto manages to slip his opponent’s attack and counter with his own strike over the top, his half dozen friends explode into cheers.

With six straight wins to advance through the bracket, Yuto, a 20-year-old student and fencer at western Tokyo’s Chuo University, has emerged ahead of the more than 2,000 competitors that originally entered the full tournament.

“It’s my first time at sassen, but it feels great to win,” Yuto tells me, adding that a fellow fencing teammate (who had bowed out of the tournament in an earlier stage) had invited him.

“Kyori machigatta! (I got the distance wrong!)” the vanquished runner-up exclaims, grasping his baton with frustration in both hands above his head.


A sense of camraderie pervades the sassen community despite its relative newness. | OWEN ZIEGLER
For whatever momentary disappointment there was, the mood quickly shifts to something much more communal as Motomura addresses the crowd of competitors and spectators and hands out trophies and awards. Many participants I spoke to emphasize that while the nature of sassen is inherently combative, there are rarely ever heated disputes about who struck who first or whether a particular point should be replayed. Indeed, tournaments like these are still rare for sassen as a whole — many just prefer to drop in and spar with like-minded players in this rented space in Akihabara, outside in a Tokyo park or anywhere else a few rounds might be had.

But what is the champion going to do with the ¥100,000 prize now rightfully his?

“We’re all going out for ramen,” Yuto says — much to the delight of his fencing comrades as they all prepare to spill back out on Akibahara’s lambent streets.
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