Japanese Yumi vs English Longbow

BoilerL1 said:

Had English bowmen in the 100 Years War been armed with Japanese bows rather than longbows it probably wouldn't have made a damned bit of difference.

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When you say "a damned bit of difference", do you mean to say they're similar and that the outcome would have been the same?

Or do you mean to say that the Japanese bows would not have made a difference?

If the former, I would agree. If the latter, I would disagree on the basis that the bows themselves perform much in the same manner and I would go so far as to say on the battlefield they're relatively equal. I can't remember if it was in this thread or another thread where I mentioned it, but yumi were using similar weight arrows as the English were on average (1000 - 1200 gr), that is livery arrows supplied to the archers for the purposes of the campaign. With even a cursory understanding of archery someone would realize that these are not the kind of arrows used with a lightweight bow. Japanese sources describing bows frequently mention high draw weight bows (though the terms they used were in referring to how many men it took to string such a bow), and the importance of being able to penetrate armour. Knowing that lamellar is fairly resistant to arrows, the fact that such an importance was stressed in Japanese sources suggests that they weren't using light weight bows at all. They would have to use bows capable of delivering at least 120 J in order to penetrate the armour.

This is a post I made last year concerning formulas and Kinetic Energy.

Thegn Ansgar said:

Let's go at it from a different angle then. You wish to know, so I gave you the formula to find out. But I'll gather the information for you.

A average reproduction of a medieval boar spear (always used two handed), weighs around 3 kg (6.6 lbs), with a length of 2.09 metres (82.5 inches). Because the range of a spear is not simply just it's length, let's say at 3 metres distance. With the formula KE = 5 x r x m (this formula ignores air resistance and thus is the initial KE. Given that air resistance does not apply to a spear because of how close range it is, the formula is appropriate) we get (for it's initial Joules, ignoring velocity):

KE= 5 x 3 x 3
KE= 45 J

Now let's go with an arrow. Average weight of an arrow fired by a medieval longbow was 900-1000 grains (0.06-0.065 kg). The optimum cited distance for a killing range of a longbow is around 30-40 yards (27.4-36.5 metres). We'll go with the shorter range just to make it more powerful, and we'll go with the heavier arrow as well.

KE= 5 x 0.065 x 27.4
KE= 8.91 J

Now let's go even further and include the velocity for both.

For the velocity of a spear thrust, I took it from Richard A. Gabriel's book "From Sumer to Rome: The Military Capabilities of Ancient Armies" which gives a one handed overhand thrust of a spear the speed of 55 feet per second (16.76 m/s). I would presume a 2 handed spear thrust would be faster, because it is utilizing more muscles and provides more stability, but I went with this because it's the only given measurement I've come across.

For Boar Spear
KE= 1/2 3 x 16.76^2
KE = 1/2 3 x 280.89
KE= 421.34 J

The velocity of an arrow from a 150 lb bow comes from Sam Fadala's book "Traditional Archery" and is 200 feet per second (60.97 m/s).

For 1000 grain arrow
KE= 1/2 0.065 x 60.97^2
KE= 1/2 0.065 x 3717.3
KE= 120.8 J (Coincides with the theory that to penetrate plate armour requires around 120 J, and that is achieved at around 30-40 yards in proper tests).

Difference: 300.54 J

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At 30 yards, a 150 lb English longbow is delivering 120 J. I'm inclined to think that the Japanese were using yumi at similar draw weights in war.

The big misconception about yumi from today is that there aren't any modern bowyers making war yumi, whereas you can find at least a fairly sizable amount of bowyers making European warbows. The reason for this is fairly simple when one takes into account what occurred to Japan at the end of WW2. All military purpose things were discarded and anything that related to it was left to die out. It's one of the reasons why kendo ended up becoming so sportified. If you look at kendo prior to WW2, it's much more martial and closely resembles HEMA of today, with using properly weighted simulation weapons, grapples, joint strikes, etc.

So when the question of "Why don't we see any high draw weight yumi?" occurs, it can be answered fairly simply. Originals that existed were discarded, and the craft to make them was neglected and left to die.

Video of Yumi against the Longbow
For all it is worth



Sorry. I just read this was already posted earlier, after I posted it.
Those two bows had matching draw weights in the show.
That might not be the case when in real use in the past. Until that is known, and used as basis to compare, the answer will not be known.

Pancho35 said:

English Longbow > Every other bow in the entire world. Nothing can match its range and power.

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Every warbow in the world has a similar range and power to the English longbow. The only difference is the way they were constructed and how they were deployed in battle.

So this thread is about effectiveness and not what looks cooler? When I clicked on it, I could only see the poll which did not state what we where voting on. Im glad I choose longbow, because I have heard that the english/welsh longbow, D section bows outranged the yumi and had/have greater draw weights. The yumi is easier to use on horseback, because you hold it two thirds down its length unlike most bows. However composite bows especially the more heavy ones used by people like the turks, mongols and other eurasian horse nomads could be used on horse back just as well and had draw weights and ranges similar to the english longbow.

The yumi does look cool and elegant though, and quite unique, are there similar types of bows to it that have been used in other parts of the world?