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Episode 78: Ninja Myths - Walking on Water, Catching a Sword, Catching an Arrow

  • Running on water (using special shoes): busted
  • Catching a sword: busted
  • Catching an arrow: busted

Ninja fans will be disappointed as the MythBusters busted several ninja-related myths. They investigated several skills that ninjas mythically possessed but were unable to replicate any of them. While it is debatable whether or not ninjas actually existed, one historical theory about ninjas is that they were peasants who developed unusual fighting techniques to defend against the samurai class. Their skills were reputed to be 'supernatural.' The MythBusters don't have supernatural abilities, so they relied on their usual means for testing.

Dale Seago of the San Francisco Bujikan dojo served as their ninja expert during the testing of these tests.

Running on Water

Myth: Ninjas could walk on water using the aid of mizugumo


Mizugumo (Japanese for 'water spider'): flat wooden disks meant to be strapped to the feet

Adam and Jamie wanted to test if mizugumo would have allowed ninjas to walk across water. Adam manufactured a pair using pine board cut into four quarter-circle pieces and a rectangular center piece. The entire contraption was laced together with twine.

Here's a photo of mizugumo in a Japanese museum:


photo by markcbarrett

Adam sunk like a rock as soon as he stuck his first foot in. He decided to do go crazy fast for the second run, "like cartoon," for the second run -- same result.

Adam: "I don't know about you, but these seem a little cumbersome to me... the important thing is I look damn good"

As it turns out, mizugumo were actually meant for rice paddies and mud flats, like snowshoes.

Adam's ninja feet

Adam designed his own set of buoyant ninja feet using snowboard boots, several layers of packing foam, aluminum sheeting on the sole, and a lightweight rail for rigidity. He calculated that the foam displacement would give him 265lbs of buoyancy.

Adam's first test run ended quickly: he tipped head-first into the water as he got into the water too quick.

Adam: "If I had any dignity, that would have been humiliating"

On his next run, he got into the water more gingerly. He was able to stand up but he ended up falling into the water as he strained to get them moving.

Adam: "I give up on my ninja shoes. They're not stealthy, they're not easy, and they don't move"

Walking on corn starch water (non-newtonian liquid)

Jamie showed that it is possible to walk across fluid -- non-newtonian liquid. The viscosity of non-newtonian fluids increases as you apply force to it, making it possible to walk across as long as you move fast enough. As it turns out, cornstarch and water is a easy way of making non-newtonian fluid.

Adam was able to walk across their own mixture of cornstarch+water. Here's a youtube clip of people walking across a whole pool of it:

busted. The myth of ninjas walking on water may have been a result of the desire of ninjas to be mythical -- ninjas could have put wooden posts in water to make it look like there were walking on water.

Catching an Arrow

Myth: Ninjas could catch an arrow with their bear hands

Tennis-ball arrows

Their first test was simple: Jamie shot arrows with tennis-ball tips towards Adam (in protective garb), while Adam did his best to snatch the arrow as it whizzed past. Jamie's bow was with different 'marks' to indicate how far he was pulling back the bow.

  • Mark 1 (slowest): Adam was able to catch an arrow in two tries
  • Mark 3 (58mph, 3x slower than real arrow): Adam was able to catch an arrow after several tries

The tennis ball made the arrow three times as heavy and the speed was three times as slow. They decided to switch to mechanical rigs so that they could test at even faster speeds.

Arrow-catching rig

They timed their expert Dale Seago closing his hands in front of a high-speed camera. It took him 35ms to close his hands. Jamie built an evil-looking mechanical hand to Dale's speed measurements. 5 pieces of heavy chain to formed the individual fingers and lace 'tendons' were weaved through the chain and attached to pneumatic actuators. A leather work glove was added for grip.

Adam built an arrow shooting rig that consisted of a bow mounted to a steel frame. Timers were set to both Jamie's hand and the bow so that they could be triggered together.

  • Test 1 (170mph): the hand rig was 2ms slower than Dale and missed the arrow
  • Test 2: based on the first test, they were able to calibrate the timer exactly. The glove closed at the correct time but the arrow was able to slip through -- Dale's hand speed was too slow.
  • Test 3 (super-fast hand): they spring-loaded the hand rig to close five times faster than a human hand. At this speed they were able to seize the arrow out of mid-air.

busted: it took a mechanical hand operating on a timer at 5x human speed to catch an arrow

Stopping a Sword

Myth: Ninja could stop a sword with their Hands

See also: Cutting a Sword


  • Sword-swinging rig: They were able to resurrect the sword-swinging rig from Cutting a Sword myth. This time they set it up to swing downwards instead of sideways.
  • Fake hands: they were able to catch some ballistics gel hands from dental alginate molds of Tory's hands
  • Sword-catching rig: They built a new rig to swing the fake hands together.
  • Trigger switch: As the sword-swinging rig swung downwards, it clipped a trigger switch that released the sword-catching rig. The location of the trigger was adjustable to change the timing.


They needed to measure hand strength for the sword-catching rig. The build team took turns slamming their hands together on a measurement pad. Grant had the strongest strike with 1000N of force, so they used his data to to calibrate.

They also had to measure sword-strike speed. Tory, Adam, and Grant all took their swings at the ballistics gel head in front of a high-speed camera and measurement grid. Grant again did the best with a ~47mph strike.

The sword catching rig performed to the correct speed but the hands bounced when they came together, creating a small gap through which the sword could slip. Tory strengthened up the rig and was able to eliminate the bounce.


Test 1: The rig caught the sword... on the rebound. After the sword bounced upwards from the fake head, the sword-catching rig came together and seized the blade.

Test 2: Grant moved the trigger to release the hands even sooner. It wasn't soon enough as the sword penetrated the head to the eyebrow.

Test 3: They moved the trigger again and caught the sword. However, the sword-catching rig triggered about 5ms too early and the sword was stopped mostly because the sword sliced through one of the ballistics gel hands in its way.

Test 4: Grant added a timer to give them even more precise control over the timing. The hands came together right as the blade passed between, but the sword still passed right through, slicing a bit of the hands.

They visited the expert Dale Seago for his opinion on the myth. While he said that they prefer to evade, he did show how a sword could be stopped with the hands. He put shuko, ninja climbing claws, and Kari swung a dulled sword right at him. Instead of clamping both hands together on the blade, he instead raised one of his shuko claws up and stopped the blade with one hand. With an assistant, he also showed how he could absorb the force of the swing and then redirect the strike towards the attacker.


Season 5, ninja myths, water myths,


Sorry, but catching an arrow IS possible. Ronald Duncan did it on Thrillseekers in the 1970s. Proof is shown in the video on this site.

i wana know how jamie built the hand, i have been tryin to build one in my basement with bike chain, rubberbands, and string. any ideas?

send them to

I have seen on two places where someone actually caught an arrow. The first time was someone on Ripleys that did it. I would like you to know that in catching the arrow it is not a case of just grabbing the arrow but changing the trajectory of the arrow that was fired at you. Thus allow more time for the fist to close around the arrow as your hand changes its trajectory.
Please also see

The arrow shot in the Ripley's clip was clearly shot at slow speed. The MythBusters episode showed that its quite easy to catch an arrow going slowly -- even Adam could do that.

I also would like to know how to build the hand. I am trying the same things, but can not figure out how to put on the string or rubber bands. Thank you

My problem with the arrow bit was that in the slow motion of the high speed hand shot, it doesn't even start closing till the arrow is pretty far. When adam was trying to catch the slower arrows, he said he had to anticipate it. So he had to start closing and moving before it got there.

I'd like to see if the human speed could do it if it started sooner. Plus I doubt the catching is usually done from that close to the firing point.

Yes, but how did they get rid of all that non-newtonian cornstarch? --C&R

Has no one seen the footage of Shigeru Oyama sensei stopping a sword with his palms? I can't believe the mythbusters have not been busted on this one. Just type "old footage sword catch" in youtube.

I have a comment on the arrow catching thing. There was this guy in Ripley's Believe it or Not who catched an arrow blind-folded. They even use a modern bow capable of delivering an arrow 200 fps. To me the myth is confirmed.

I didn't see the show itself i'm afraid but it seems to me the mythbusters missed the point (no pun intended!)

Walking on water was only ever for short distances and did not use the type of shoe shown, read Hatsumis/Hayes book on Ninjutsu for details.

Catching a sword I have done several times but not that way! You cant factor out all the other variables like body positioning which is what happened their. Also, the shuko is how we would normally do it, what fool catches a sword barehand outside hollywood?

Catching an arrow involves moving out of the way and tracking it, not just standing there and trying to close your hand in time.

Just my .01 (im divorced..the wife has the other .01)

Now don't get me wrong mythbusters i love your show but i do ninjutsu under the bujinkand and if you check ninjas were often farmers and had many items at their disposal. One of these items was a home made sand paper made with crushed shells, seeds, and sand that were bonded to parchment using natural gum. Now ninjas usually didn't try to stop swords they would try to get away but if they had to sometimes they used sandpaper to help create lots of friction. But that might not stop a sword but noone used bare hands.
Thx love your show.

I would just like to comment on that sword catching thing... but not saying Im an expert on it but, I think that move would be more probable if they aimed the catching mechanizim closer to the base of the sword where a samurai warrior would hold it... A better chance at least to catch it being slower than the actual tip of the sword. Also, I saw that move on a Voltes 5 episode where BigBert was trying to catch a butterfly... hehe

Hey guys, now I don't much care for Ninja(s), but I thought I'd post a comment to say that I play paintball a sport where you are shot at by projectiles that are flying at 300fps, I looked up the speed of an arrow and found it to be arround the same speed (infact most sources say its a little slower).

Now the reason I am saying this is because, whilst playing paintball I find it quite easy to dodge incoming paintballs and to catch them (or atleast put my hand in its projectory, they usually burst, and it hurts... ...alot).

This being said I see no reason to doubt that someone half my size, who was faster and more agile could dodge and/or catch an arrow.

I think this myth needs to be done again...


PS: why does it have to be a Ninja myth, I'm sure knights could smack arrows out the air with their swords ;)

Hey guys, I just did a bit of math, with a reaction time of 165ms (my reaction time), + 35ms to shut my hand (assuming I can close my hand at the same speed as that guy on the show), I calculated that I could see the archer fire his bow, and close my hand by the time the arrow as traveled 60 feet, I think with a bit of practice I should be able to catch arrows at say 100 feet with relatively no difficulty.

Just my 2 cents.

Yeah, I'm disappointed with the arrow-catching thing. The martial arts lore I've heard about says that stopping an arrow is an act of “aiki”, or synchronized intent — in other words, reading the bowman’s movements to predict when he’ll shoot. I’d like to see *that* myth properly investigated.

It's not that distance lets the arrow slow down. No!
A longer distance allows for longer reaction time. Hitting a 90 mph pitch is WAY easier when the pitcher is way farther away. Even a slow reaction person with a slow swing can time it just right.

Guys sorry, all ninja dreams aside, if someone fires an arrow at you you are probably going to die rather than catch it.

Yes it might be possible to catch it, but in battlefield conditions with a 1000 other things going on is it going to work... NO. All the techniques of avoiding a strike and striking back in most martial arts work when in training but when put into live combat require adaption and more force than used in training. Just look at the early UFC and you will see how SCRAPPY most fights are no matter who is fighting

the SHUKO, or ninja claw, was also used to climb trees as well as being used as a wepon.
It was a great killing tool for the ninjas against the samuries when having the need to fight them.

if your life depended on it
and you practiced ALOT
you could learn to catch an arrow yes,,,,,,,,,,

you cannot think & do it
it is all reflexes
and helluhh practice

in my teens,
i saw the arrow catch on tv and tryed to do it,
with my friends "help"

after a summer of practice,
at full draw speed ,
from a recurve bow ,
with very blunted arrows
while wearing padded gloves
arrows cought = 1 in 20
= {tacticaly useless}

i can still [dodge] an arrow
i did this most of the time
cause i chickened out
and this has saved my ass when attacked by a few
would-be muggers or
drivers/cell fone abusers

dodging works better
and any one can do it :-)

catching an arrow cannot be done by a simple movement of a robot hand.
not all people have the same muscle reflex.
maybe adam and jamie are not familiar with Fast and Slow Twitch Muscle Fibers.

If Adam and Jamie can't do it, No one can.

no offense but mizu gumo are meant for people with light body builds (especially children) and you dont put one foot in first or try to run on the water your supposed to take long rythmatic strides.