So, What Makes Japanese Selvedge Denim So Special?

Summary

Michael from The Iron Snail presents the ultimate guide to raw Japanese selvedge denim, explaining everything from the difference between raw and selvedge denim to why it commands premium prices. He demonstrates recreations of vintage Levi’s denim from 1942, 1947, 1952, and 1967, showing how Japanese collectors and manufacturers obsess over matching the exact texture, fuzz, bumps, and imperfections of original American denim.

The video breaks down the technical aspects of shuttle looms versus modern air-jet looms, explaining that the inefficiency of shuttle looms is precisely what makes selvedge denim special - the weft yarn loops back creating a self-finished edge that doesn’t fray. Michael covers essential vocabulary like slub, nep, chain stitch, roping, whiskers, and honeycombs, while addressing common questions about durability, washing, and fit. He explains that Japanese selvedge denim’s expense comes from slow shuttle loom production (2x cost), half-width fabric (4x cost), complex small-batch manufacturing, and historical attention to detail passed down from post-WWII American GIs who brought denim culture to Japan.

Highlights

”Japanese collectors pay thousands for the real thing”

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“Japanese Levi’s collectors pay thousands upon thousands of dollars for the real thing. So they can grab their 1942 pair of Levi’s and say, ‘Nope, that’s not right. That doesn’t look right. Look at the fuzz. Very different.’” — Michael, 0:13

”One of the leading causes of tuberculosis”

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“They were one of the leading causes of tuberculosis in the US for a very long time because the employees would suck on a component of them. And the bosses were like, ‘Stop sucking on those. It’s giving you typhoid.’” — Michael, 0:32

”This denim is filled with twigs and leaf matter”

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“This denim is filled with twigs and leaf matter. This is some of the craziest textured denim in the world.” — Michael, 0:57

”Uniqlo shrunk 0%, fancy Japanese brands shrunk 9%”

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“Uniqlo shrunk 0% and fancy Japanese brands would sometimes shrink 9%. Because when you’re making really fancy textiles with crazy yarns and you’re trying to preserve all the character possible, you get wild shrink amounts.” — Michael, 10:55

”Levi’s went in guns blazing and sued all of you”

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“Levi’s went in guns blazing and was like ‘we’re suing all of you, take all of our stuff away.’ So that’s why similar details but kind of remixed.” — Michael, 12:25

”Two pigs flying instead of two horses”

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“So we still have a leather patch but it doesn’t show two horses pulling jeans across like Levi’s has. We have an arcuate but it’s kind of different and wonky. Instead of a red tab we have a little red embroidery… you have two pigs flying if you’re doing Studio D’Artisan.” — Michael, 13:45

Key Points

• Raw vs Selvedge Distinction (2:05) - Raw denim is unwashed fabric that came off the loom; selvedge is a specific self-finished fabric made only on shuttle looms
• Shuttle Loom Explained (3:53) - Picture grid with warp (vertical) and weft (horizontal); shuttle looms pass weft yarn back and forth like throwing a baseball, creating looped self-edge
• Typhoid Factory History (5:26) - Workers would suck yarn through shuttles to thread them, spreading tuberculosis through shared shuttles across the factory
• Slub and Nep (7:40) - Slub is the veins of denim from uneven yarn twist; nep is the pimples from knots or vegetable matter caught in yarn
• Union Special 43200G (8:05) - The specific chain stitch machine from Levi’s golden age that creates distinctive roping fades on hems
• Vintage vs High Contrast Fades (8:40) - Washing frequently creates gradual vintage fades; not washing creates dramatic high contrast fades
• Fade Terminology (8:55) - Whiskers at crotch, honeycombs behind knee, train tracks along outseam, stacking from long hems
• Durability Reality (9:42) - Per ounce, fancy selvedge may not be stronger due to inconsistent yarns, slubs, neps, and low-processed vegetable matter
• Weight Compensation (10:25) - Manufacturers use 14-16oz instead of typical 11-12oz to compensate for yarn inconsistencies
• Sizing Advice (10:55) - Size up in waist and go 3.5-4% longer in length to account for shrinkage; fancy Japanese brands can shrink 9% vs Uniqlo at 0%
• Post-WWII Origins (11:35) - American GIs brought denim culture to Japan; Japanese collectors started paying thousands for vintage Levi’s
• Osaka Textile Mills (12:00) - Japanese mills perfected replicating exact dye, spin, and inconsistencies of vintage American denim
• Levi’s Lawsuit Era (12:20) - Levi’s sued Japanese repro brands for copying, leading to similar but remixed details (two pigs instead of two horses)
• Cost Breakdown (13:00) - Shuttle looms = 2x cost for slow production; half-width fabric = 4x total; plus ethical labor and sustainable water treatment
• Manufacturing Complexity (13:30) - Brands like Samurai use 15 different cotton threads, two rivet types, special patches - then make only 10 units

Mentions

Companies

• Levi’s (0:00) - Vintage 1942, 1947, 1952, 1967 denim being exactly recreated by Japanese manufacturers
• Iron Heart (10:35) - Known as “the strong brand” using Zimbabwe cotton, Egyptian cotton, Pima cotton for durability
• Samurai (10:00) - Farming their own cotton for their S500AX, using short staple cotton that adds character
• Studio D’Artisan (12:40) - Uses two pigs flying as their symbol instead of Levi’s two horses
• TCB Jeans (12:45) - Uses “Two Cap Brand” as their identifier
• Railcar (11:00) - Recommended hemming service with Union Special 43200G machine
• Vaer (6:12) - Video sponsor, D2 Meridian watch with 150m waterproof guarantee
• Uniqlo (10:55) - Referenced for 0% shrinkage vs 9% for fancy Japanese brands

Products & Technologies

• 1942 Levi’s Recreation (0:00) - Exact reproduction of vintage denim fuzz, bumps, lumps, and lines
• Shuttle Loom (3:23) - Slow, inefficient, loud looms that create self-finished selvedge edge
• Air-Jet Loom (5:18) - Modern loom that shoots yarn projectiles but requires sewn edges
• Union Special 43200G (8:05) - Specific chain stitch machine creating roping effect on hems
• Selvedge ID (2:54) - Red yarn ticker on self-finished edge identifying selvedge fabric
• Iron Heart 634S - Featured brand’s jeans
• Oni Denim 595 Kasuri - Featured slubby textured denim
• Sugar Cane Hawaii - Denim filled with twigs and leaf matter
• D2 Meridian (6:12) - Vaer dive watch, 150m waterproof, sapphire crystal

People

• Holly (4:36) - Editor, asked to add graphics for weaving explanation
• Ollie (3:48) - Asked to pull up graphics HUD

Surprising Quotes

“Japanese Levi’s collectors pay thousands upon thousands of dollars for the real thing. So they can grab their 1942 pair of Levi’s and say, ‘Nope, that’s not right. That doesn’t look right. Look at the fuzz. Very different.’” — 0:13

“They were one of the leading causes of tuberculosis in the US for a very long time because the employees would suck on a component of them. And the bosses were like, ‘Stop sucking on those. It’s giving you typhoid.’” — 0:32

“This denim is filled with twigs and leaf matter. This is some of the craziest textured denim in the world.” — 0:57

“Uniqlo shrunk 0% and fancy Japanese brands would sometimes shrink 9%. Because when you’re making really fancy textiles with crazy yarns and you’re trying to preserve all the character possible, you get wild shrink amounts.” — 10:55

“Levi’s went in guns blazing and was like ‘we’re suing all of you, take all of our stuff away.’ So that’s why similar details but kind of remixed.” — 12:25

Transcript

0:00 This is an exact recreation of the denim Levi’s was using in 1942. The exact amount of fuzz on the denim, the little bumps, the little lumps, and the little lines, all exactly as they should be in 1942. But why does it have to be an exact recreation? The answer is simple. Japanese Levi’s collectors pay thousands upon thousands of dollars for the real thing. So they can grab their 1942 pair of Levi’s and say, “Nope, that’s not right. That doesn’t look right. Look at the fuzz. Very different.”

0:24 And this obsession with making the denim perfect led to an obsession with the machines that made the denim. These big clunky machines. And fun fact about the machine, well it’s not a fun fact. They were one of the leading causes of tuberculosis in the US for a very long time because the employees would suck on a component of them. And the bosses were like, “Stop sucking on those. It’s giving you typhoid.”

0:47 An exact recreation of Levi’s denim from 1947, 1952, 1967. 100% American cotton heavyweight big beefy denim. Recreation of the blanket lining found in vintage denim jackets. This denim is filled with twigs and leaf matter. This is some of the craziest textured denim in the world. And this is some of the strongest denim in the world.

1:15 Welcome to the ultimate raw Japanese selvedge denim guide. The goal is everything that you need to know after you watch this video. You’re like, “Okay, got it. I got it. We’re good. I can buy a pair of pants.” That’s the goal because the big overarching goal is to create the greatest raw selvedge denim series the internet has ever seen. Starting here with a guide what you need to know. Then going through every single raw Japanese, American, whatever selvedge denim brand there is on the planet. Then going to Pennsylvania where our custom denim is currently being made and then going to Japan to see how the sausage comes out.

1:45 Today’s agenda. Number one, what on earth is raw selvedge denim? Number two, all the nerd terms you need to know or vocabulary. Three, is it actually stronger than regular denim? Four, why can’t you wash it? Five, how should it fit? And then six, my favorite thing. Number one, why is it so expensive? And number two, what is actually so special about Japanese selvedge denim? What is so cool about it?

2:05 Raw denim and selvedge denim usually locked at the hip. They usually sound like one thing. They’re actually two different things. You got your raw denim, you got your selvedge denim. All denim really, all fabric at one point in its life is raw, but not all denim or all fabric is selvedge at one point. Raw is really just fabric that came off the loom. It can undergo some processing like you can sanforize denim which is you steam it and you rub it between machines so that way it gets most of the shrink out. Or you can skew it which is usually if you have loom state denim which is denim that comes right off the loom. Nothing is done. It will twist. The seams on the side of your legs won’t be on the sides of your legs after you wash it the first time. They’ll go towards the front. Leg twist. All raw denim is is just denim that hasn’t been washed by you or by the manufacturer.

2:47 Selvedge denim on the other hand is completely its own thing that has a specific process. It can only be made on one machine. It’s a self-finished fabric. So this is called a selvedge ID. You don’t have to add stitches to the edges here because it doesn’t fray. It’s a self-finished edge. Self-edge. You can also have selvedge fabric that doesn’t have any selvedge ID. All that is is when you’re making fabric, it’s just a giant grid. So, picture a bunch of just vertical lines and the edges of those vertical lines, you use white yarns on the side instead of indigo dyed yarns. And then you have one red yarn to be your selvedge ticker. That’s it. You could do that with any loom, but specifically selvedge denim is made on a shuttle loom.

3:23 This is going to sound like I’m just going to roast shuttle looms for a second, but it’s very important that we know this. They’re very, very inefficient. They make denim really, really slow, and they use a lot of power. They don’t have even tension or the most even tension compared to modern machines. They’re really, really clunky. They’re really, really loud. They shake everything and they do one thing that no modern loom does and they even try to do. Modern looms try to reproduce it but they can’t because it’s so inefficient that they never will.

3:53 Okay, picture a grid. That is the basis of woven fabric. You have your warp which is going up and down and you have your weft which is going side to side. You start off with your warp and you set the warp in the beginning. All of those yarns are already set. They’re big long strands that you can see on any weaving video. Those are good to go. They’re ready to go. What we need to do now is get the weft yarn through the warp yarn. So, you have what is called a shed, which is some warp yarns up here, some warp yarns down there, and you shoot a weft yarn through. Then, the reed pulls that yarn forward down towards the finished cloth at the bottom, and then the shed goes and switches.

4:35 The big thing that changes is how we get that weft yarn through to the other side. If it’s a shuttle loom, pretend I have a baseball that is full of yarn. When I throw the baseball, the yarn goes that way and my friend catches it. But that process is kind of inefficient because I have to throw it to him. He has to catch it, slow the momentum, then he has to get it, wind it up, and throw it back to me. A modern loom though, instead of playing catch with my friend, I’m just shooting a projectile at him or just a yarn at him again and again and again and again. So I don’t have to wait for it to come back. I can just go boom boom boom boom boom.

5:12 And the weft yarn looping instead of being cut is why selvedge fabric is self-finishing, why it’s a self edge. When you have modern denim that is done with an air-jet loom, for example, you’re basically sewing those loops back on and that’s how you close it up. That’s the big difference.

5:26 Anyway, all that is to say, typhoid. Why? What happened with typhoid? I’m glad you asked. Shuttles, there’s a lot of comparisons to an actual gun, like how they reload and everything like that. In early shuttles, they didn’t automatically thread the yarn when you put it in. It didn’t automatically come out the shuttle. So, there had to be more user intervention. You had to load the pirn in and then you had to get the yarn out of the shuttle. And that was hard to do. So, what people did way back when was they would put the pirn in and then they go and they suck the yarn through and then boom, when that shuttle would run out, it would get ejected into a bucket. Someone would take the bucket of empty shuttles. They would reload them and it would go around the factory. So, everybody had the same shuttles and they were going again and again and again and spreading typhoid like crazy because of that.

6:12 Hey, pretend this is 150 meters down and the deep dark scary depth below. Plop. No problem for the D2 Meridian, practically lives there. This is the Vaer D2 Meridian. A certified hunk of a wristwatch that comes with a waterproof guarantee. If your screw down crown is closed and your watch gets filled with water, for example, 150 m in the depth, no problem. Vaer has your back. This is covered.

7:05 Okay, so that’s that. Welcome to the vocab section. This will be pretty rapid fire, so let’s go.

7:10 Slub, the vein of denim. See these big vertical beefy lines sticking up? That is slub. Often caused by uneven yarns. They’re not spun with a consistent twist. So, some parts of the yarn are fat. Other parts are slim.

7:28 Nep, the little pimples and moles of denim. They look like little blue or white dots or whatever color the fabric is, but little dots, little puffs. That is often times caused by knots in the yarn or plant matter like vegetable matter, could be leaves, could be twigs getting caught up and gnarly in the yarn.

7:50 Chain stitch. It’s just a stitch. But most of the time, if chain stitch is being brought up in the world of raw denim, they’re not talking about just a stitch. They’re talking about the machine that is used to make the stitch specifically, the Union Special 43200G that was used in the golden age of Levi’s. You can do a regular chain stitch and when it fades it will pucker a little bit and the fades will be very straight. But if the chain stitch is done with a Union Special machine, the hem will look nice and ropey and the fading will be called roping. The Union Special is harder to work with, harder to maintain, shows a certain amount of skill, and it’s a big cool nerdy detail.

8:40 Vintage fades versus high contrast fades. The big difference is how often do you wash your denim? If you wash them a lot, you get vintage fades, which is a very gradual fade in color. High contrast fades are you not washing your denim a lot. So, where there’s a lot of wear, that gets really light, but the rest of the piece stays very dark blue.

9:00 Crotch fades, excluding your phone, are called whiskers. Fades behind your knee are called honeycombs. Fades along your outseam, train tracks. Wearing your denim too long so it fades on the bottom stacks is called stacking.

9:25 Okay, now the big question. Is this fancy selvedge denim more durable than your regular not fancy denim? Um, no. Well, yes. The cotton in here is from a Japanese cotton. This is a Samurai from their cotton project where they are farming their own cotton. It’s insane. But that is a very short staple cotton. That’s really amazing and cool and it adds a ton of character to the denim, but that doesn’t make very strong yarns and very strong denim.

9:55 Also, with all fabric, the yarns need to be twisted just the right amount to hit max durability. It’s all about friction and how things rub together. And making something like this might not be the most durable because it’s a very low tension. And slubs and neps and everything like that. That’s, you know, knots in the yarn and inconsistent yarn thicknesses. That all decreases durability. Probably not by a lot, though.

10:22 A lot of fancy denim makers, they do very low processed yarns because it adds a lot of character. It’s cool to have vegetable matter in the fabric. But if you’re talking pure strength, that’s also not strong. That’s just inconsistencies in the yarn. It’s more chances for things to rub together and degrade over time. So, it does weaken the fabric as a whole. But you’ll notice with most crazy denims from these crazy manufacturers, the denim is not a typical denim weight. It’s not 11 oz or 12 oz. It’s 16 or 14 at the minimum. It’s very, very heavy to make up for the inconsistencies in the yarn and in the weaving.

10:55 Also, it’s important to note that most selvedge denim brands have a more consistent denim. This Iron Heart, they’re kind of known for just being the strong brand, but they have more consistent denims. They use Zimbabwe cotton, Egyptian cotton, Pima cotton, whatever it may be. That is far stronger than what you see from a brand like Levi’s or something like that. This is an actual tank.

11:15 My advice is and always will be size up a little bit. It doesn’t have to be crazy in the waist and then length. Go longer than you think. Most of us now are very used to just regular clothes bought from big stores who work really hard to make sure all the shrink is possibly out. When we did the t-shirt comparison video, Uniqlo shrunk 0% and fancy Japanese brands would sometimes shrink 9%. Because when you’re making really fancy textiles with crazy yarns and you’re trying to preserve all the character possible, you get wild shrink amounts.

11:45 I’ll usually go one size up from my pant size because it will shrink a little bit the first time you wash it. And then for length, I get jeans that are like 3.5% to 4% longer, which is a good amount longer. And that way after I wash them a few times, if they’re still too long, I can get them hemmed. I can send them to Railcar or someone that has a 43200G and they can hem them the right way, but they fit me exactly how I want them to after all those washes.

12:15 Okay, finally, the best part of this video. Why is raw Japanese selvedge denim so expensive? And what’s so cool, magical about it? Why is everybody obsessed with it?

12:25 Post World War II, American GIs are in Japan, and they’re basically just throwing their culture around everywhere. They’re like, “This is rebellion. This is Western culture. This is what we do. And these are the pants that we do it in.” And the Japanese market was like, “Those are pretty cool pants. I would like to get some of those.” So they start importing Levi’s and they’re very, very expensive, but you know, it’s kind of the cool rebellious thing. And you see it in Japanese films for a while.

12:55 There wasn’t a real denim competition in Japan at the time. So while all of that is happening, a bunch of textile mills in Osaka are hard at work replicating denim, being like, “Okay, this is how they dyed it. This is how they spun the yarn. These are the inconsistencies. These are the fiber lengths that are being used. Here’s how we can recreate it perfectly.” Like that 1942 pair of Levi’s we have right here.

13:20 So now we’re going into the early Levi’s repro brands that were copying Levi’s a lot until the point where Levi’s went in guns blazing and was like “we’re suing all of you, take all of our stuff away.” So that’s why similar details but kind of remixed. So we still have a leather patch but it doesn’t show two horses pulling jeans across like Levi’s has. We have an arcuate but it’s kind of different and wonky. Instead of a red tab we have a little red embroidery.

13:45 What you have is this really cool paying homage to this American crazy brand, but also adding your own Japanese influence, your own heritage into it. So, you have the story of the Peach Boy with Momotaro. You have two pigs flying if you’re doing Studio D’Artisan. You have Two Cap Brand if you’re TCB Jeans. All this stuff is kind of getting mixed in.

14:10 But what makes it so expensive, you may be asking. First thing, like I said, is shuttle looms - super inefficient. They’re very loud. They make very slow denim. And they also make it at half width. But that slower process combined with higher quality, more ethical labor, sustainable water treatments when you’re dying and stuff like that, that puts the denim cost around two times. And then since the denim is half width, that makes the denim around four times more expensive than regular air-jet loom, projectile loom denim.

14:45 From a logistics standpoint, raw selvedge Japanese denim, everything like that, it’s usually a pain in the butt to make. If you’re a brand like Samurai, you might say, “Okay, we use 15 different threads. They’re all cotton, so they break easier. We have two different types of rivets that go inside of the same jean. We have a special patch that goes on here to emulate what a washed Levi’s patch looked like in the 1940s.” That is a logistical nightmare. And you say, “After all of that, we’re making 10 of these.”

15:08 But if you’re into it, you get all these really cool details. It looks like a hand-sewn arc. It’s gorgeous. Wild fabric that fades with a ton of character and is super interesting to look at all the time and really just cool stuff like that. And it’s very, it’ll suck you in. That is that. I will see you next week for the wax jacket video.