UL Shirt


¥13,200 Tax included


A versatile, ultralight shirt

At only 78g, we’ve created a shirt that’s thinner and lighter than any other shirt.

Wear it directly on your skin and roll up the sleeves like a T-shirt, or wear it over a base or midlayer as a windbreaker—this shirt lends itself to a wide range of uses.

The excellent breathability of the Pertex Quantum Air fabric means that sweat dries in an instant and with a fit that allows outside air to easily circulate through the garment, this shirt keeps you comfortable even on hot, sweaty days. Meanwhile, the collar can be turned up and fastened in strong winds, making the shirt adaptable to rapid weather changes.

The size has been revised since 2021 for a more relaxed fit.


  • Blue
  • Burgundy
  • Light Olive
  • Friar Brown
  • Storm Gray
  • Black


Made in Fukushima, Japan

Pertex Quantum Air (100% Nylon) 48g/㎡
C6 DWR (Durable Water Repellent)
69g(Size XS)
78g(Size S)
83g(Size M)
88g(Size L)
95g(Size XL)
UNISEX | XS / S / M / L / XL

Product Story

“I wanted a shirt”

Akira Natsume, Yamatomichi Founder

A merino wool base layer with an ultralight wind shell or a breathable rain shell seems like the perfect choice for the ultralight hiker. However, always going hiking in the same clothes gets a bit boring eventually, and I think hiking should be not just practical but also fun. That’s why I thought a shirt for variety would be a good addition to our lineup.

Read more

For the material, my initial choice of 100% merino wool was certainly comfortable, but the fabric weight of 200g/m² was just too heavy and warm during the hot Japanese summers. As a self-proclaimed wool lover, I was tempted to go ahead anyway, but somewhere in my heart, I wasn’t convinced that wool was the right answer.

While I was in the process of trying a variety of other materials other than merino wool, I stumbled on the idea of using the lightweight Pertex Quantum Air fabric that’s used as the facing material for our Alpha Anorak. Up to that point I had been keen on using natural fibers like wool and bamboo, but then I started thinking that if I was going to focus on lightness it might be ok right to go with a 100% synthetic fiber, and at 50g/m², the Pertex Quantum Air is almost as light as air!

The resulting prototype was as extraordinarily light as I had imagined, and many people were surprised when they picked it up. The one thing that worried me was its odor resistance. Since the shirt was 100% nylon, I didn’t anticipate odor resistance like what you get with wool or bamboo. As someone who wanted to avoid going around the mountains in smelly clothes, I was concerned, but as I actually tested the prototype I soon understood that I had nothing to worry about. This UL Short Sleeve Shirt is not only light, it also dries super fast.

You can wring it almost completely dry in a towel after washing and the remaining moisture will dry quickly when you walk around wearing it. Thanks to this, if you come across a stream or lake on your travels and give it a quick wash, you can just put it right back on again and keep on going.

Form and Function

Lighter than T-shirt

At only 78g, we’ve created a shirt that’s thinner and lighter than any other shirt.

The fabric uses the Pertex Quantum Air, which is made of strong nylon woven together at a high density. It is strong but ultralight, only weighing about 50g/㎡, achieving both breathability and durability.

Versatile, Ultralight Shirt

The uniqueness of the UL Shirt lies in its versatility. The ultra-thin, ultra-lightweight Pertex Quantum Air fabric and the basic “shirt” design offer maximum usability in a wide range of situations.

You can wear it as a short-sleeved shirt with the sleeves rolled up, or as a wind shirt in combination with a base/mid-layer.

Super Compact

The shirt is so compact it fits in the palm of your hand when folded, making it perfect as a change of clothes when hiking or traveling.

Raised Collar

Buttons on the inside of the collar allow it to be turned up and fastened to shield from the wind and sun.

Super fast-drying

Quick wash? Just rinse in a stream and wring the shirt and you’re good to go.

Moisture Content after 15 min of Spin-dry

The chart below shows the moisture content in the fabric after 15 minutes of drying. It compares our shirt with the base layers of a major manufacturer, as well as our merino wool products and a standard cotton shirt.

The lower the moisture content, the faster it dries. The graph shows that the Shirt has only 1.5% water content after 15 minutes of drying. In other words, almost completely dry.

Our UL Shirt dries slightly slower than Patagonia’s exceptionally fast-dry Capilene Cool Lightweight, but it still has a much lower moisture content than base layers made of common quick-drying synthetic fabrics.

On and Off the trail

Wear the shirt as a thin windbreaker on top of one of our Merino T-shirts or bring it as a change of clothes for when you get off the trail and head for the nearest bar.

Form follows function

Woven fabric, which is often used as a material for shirts, is densely woven by warp and weft yarns. For the same weight and material, it is usually more windproof, dries faster, and more durable than knitted fabrics, which are commonly used for base layers.

We chose snap buttons to make the buttoning and unbuttoning as fast and easy as possible. The cut is wide to allow for ample ventilation.

We decided on an open-necked turndown collar without a neckband to avoid trapping heat around your neck when moving, while still allowing you to turn up your collar and secure it in the cold, making this shirt work in a wide range of temperatures.

We didn’t feel the need for pockets, so left these out on purpose.


Amazingly light and fast-drying Pertex Quantum Air

In the harsh mountain environment, where the weather and temperature rapidly change with strong winds and intense sunshine, both breathability, and windproof property are required at the same time. The UL Short Sleeve Shirt is made of Pertex Quantum Air, a 20 denier fabric that is ultralight, yet has excellent durability and breathability.

Pertex Quantum Air (100% NYLON) 48g/㎡
20d x 20d Ripstop
C6 DWR (Durable Water Repellent)

Tear strength (Pendulum method) measured by JIS L 1096 D
Vertical: 0.9kg, Horizontal: 0.8kg

Tensile strength measured by JIS L 1096 A (Strip method)
Vertical: 35.6kg, Horizontal: 30kg

Breathability measured by JIS 1096 A (Frazier method)


For more sizing examples, please click “READ MORE”.

Read more

推奨サイズ/Recommended Size

Size XS S M L XL
42~53 51~61 59~69 67~78 76~85
78~84 80~88 84~95 92~102 100~110

Product Size

Unit: cm
Size XS S M L XL
着丈/Length 67 70.5 72.5 75 77.5
肩巾/Shoulder Width 44 47 49 52 56
身巾/Body Width 55.5 60.5 63 67 72
裾巾/Hem Width 51 56 58.5 62.5 67.5
袖丈/Sleeve Length 52.5 58 59 60.5 62
袖口巾/Sleeve Opening 9.5 10 10.5 11 11.5

The size has been revised since 2021 for a more relaxed fit. Compared with older version, 2021 version is…
Size XS, S, M: Body width is 4cm larger.
Size L: Body width is 6cm larger, length is 0.5cm longer.
Size XL: Body width is 10cm larger, length is 1cm longer.

Please Note

Snag and Pilling

The Pertex Quantum Air may develop snag and pilling when constantly rubbed against a rough surface.
Outlined below are the situations where snag and pilling are particularly likely to occur and how to repair them.

Read more

How Snag and Pilling Occur

The following shows a couple of examples of pilling and snag on our UL shirt. Please note, however, that similar situations below don’t always result in pilling.

Friction and contact against hard and rough objects such as Velcros and coarse mesh.

Repetitive contact and friction in the same spot, often with shoulder belt and hip belt of the backpack, or car’s seat belt.

*Damage can be more noticeable when the fabric is wet with sweat.

Temporary Repair

Lightly stretch the fabric so that the distortion of the fabric is corrected. If it is still snagged and distorted, use a low-temperature iron, apply a covering cloth and reshape the fabric while lightly stretching it.

Using a pilling remover, cut the furballs on the surface of the fabric. Do be careful not to cut the fabric of the shirt. Please note that when pilling is removed, the yarn composed of long filaments may be cut and the strength of the fabric is weakened or a very small hole may occur in the fabric surface. You can also lightly sear the pilling with a lighter to melt the fuzz. This will reinforce the area around the pilling and prevent further tearing, but too much burning may cause holes in the fabric and harden the melted area.

Disclaimer: Please note that the above is only provided for reference and that we do not accept any responsibilities for any damages as a result of following these instructions.

Care Instructions

  • Machine wash below 40°C.
  • Wash separately or use a laundry net bag.
  • Line dry in the shade.
  • Tumble dry below 60°C.
  • Do not bleach and do not use fabric softener.
  • Iron on low, cover the pants with a cloth. Do not steam.
  • Do not dry-clean.


  • We only accept payment by credit card. We currently do not accept payment via bank transfer from overseas accounts.
  • We accept the following Credit Cards: Visa, Master, American Express, and JCB.
  • To download your receipt, please click the link included in the Dispatch Notice, which we will send by email as soon as the items are dispatched.


We will ship by DHL for overseas customers (excluding China, Hong Kong, Taiwan, Korea and Russia). For customers in China, Hong Kong, Taiwan, Korea and Russia, we will ship by EMS only. Shipping costs vary depending on your country and region.

Size Exchange

  • Overseas customers who need to change the size of their order, should note that the time needed for shipping will vary greatly depending on your country of residence.
  • We only accept exchanges when the item is unused (except for fitting).
  • If you wish to exchange the size of the item, please contact us within seven days of receiving your order.
  • Exchanges can only be made for the same color in a different size.
  • If the size you wish is out of stock, we will suggest a different color.
  • If the product is out of stock, we may simply have to ship the item back to you.
  • All shipping costs to be carried by the customer.
  • We will only send the exchanged item to you, upon receipt of return shipping cost via PayPal.
  • Please be aware that some countries charge customs duties depending on the price of the item.
  • We are unable to answer any questions on local customs. Please contact your local customs bureau.


We accept repairs for all of our Yamatomichi products. For inquiries on repair services including patching the holes, repairing with extra components, or fixing the items damaged over time, please feel free to contact us from the “Repair” section of the SUPPORT page.

Restock Alert

UL Shirt


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