山と道

UL Rain Jacket

134g (PU Sosui)/ 123g (PU Shinsui)

¥34,100(PU Sosui)/ ¥36,300(PU Shinsui)

Introduction

Come rain or come shine

This ultra-lightweight triple-layer jacket for hiking and fastpacking has an easy adjustable double zipper and ventilates well during both rain or shine. It’s light and breathable enough to be worn both as a rain jacket on a rainy day, or a light shell on a sunny one.
The fabric is ultrasonically welded to the fabric to prevent water penetration in the seams. The PU Sosui is made of Pertex Shield Pro, a polyurethane hydrophobic porous membrane that constantly removes moisture from the body while moving. The PU Shinsui version uses the regular Pertex Shield, a polyurethane hydrophilic non-porous membrane with an ultra-thin seven denier outer fabric for superior lightweight performance.

Color

  • Blue
  • Red
  • Deep Forest
  • Navy
  • Ebony
  • Nomad

Specs

Made in Akita, Japan

PU Sosui
Material:
Pertex Shield Pro 58g/㎡ (100% Nylon)
Weight:
134g(Size XS)
142g(Size S)
150g(Size M)
157g(Size L)
165g(Size XL)

PU Shinsui
Material:
Pertex Shield 47g/㎡ (100% Nylon)
Weight:
123g(Size XS)
133g(Size S)
140g(Size M)
147g(Size L)
154g(Size XL)

Size:
UNISEX | XS / S / M / L / XL

Product Story

The world's lightest
double zipper rain jacket

Akira Natsume, Yamatomichi Founder

The UL Rain Hoody was our first rainwear product and really changed the game. By doing away with the zipper, we created a soft, comfortable, and super light piece of rainwear with very little chance of the rain getting in. But many of our staff at Yamatomichi love trail running and fastpacking, so they wanted a fully zippable jacket that could provide better ventilation to let off heavy sweat during intense activity.

The UL Rain Jacket may not feel as novel as the UL Rain Hoody. However, because it is more orthodox, there were many things that needed to be considered, and it took more time than expected to complete.

The biggest change from the UL Rain Hoody is the double zipper, which allows you to easily regulate your body temperature and ventilate your body while on the move. It’s a bit tighter than the UL Rain Hoody as it can be opened and closed from the top and bottom to allow more air in, but I think it feels a lot looser than the tighter, lightweight jackets that are mainly used as running rainwear. This difference in shape allows you to move around with ease and make the wearer less likely to get clammy.

For the zipper, we chose YKK’s No. 3 water-resistant Vislon for ease of opening and closing. It takes less effort to open and close the zipper than the coil zippers used for our backpacks, and is super easy to use.

The hood is what took us the most time to get just right. I like hoods, and I don’t want to use a product that makes it hard to move around with the hood up. It took several prototypes to create one that fits to a certain extent and still allows for easy neck movement. I think the result is a basic rain jacket that’s high in overall quality and the little details are just right.

The PU Sosui using the Pertex Shield Pro is especially waterproof against rain, and its direct moisture permeability makes it ideal for both rainy and sunny days. The UL Rain Jacket isn’t the lightest rainwear in the world, but it is one of the world’s lightest rain jackets with double zippers that uses a three-layer, breathable, waterproof fabric.

READ MORE

Form and Function

PU Sosui for the active hiking

The PU Sosui is made of the ultra-lightweight and highly breathable waterproof material Pertex Shield Pro.

The breathable, waterproof layer of Pertex Shield Pro has a porous membrane with countless tiny holes that are smaller than water molecules, which directly dissipate unpleasant moisture from your clothing to keep you comfortable at all times, even when you are active.

It is a high-performance jacket with an excellent balance of waterproofness, breathability, and lightness that allows for comfort on both rainy and sunny days.

The super-light PU Shinsui

The Pertex Shield fabric used on the outer layer of the PU Shinsui is seven denier ultra-thin nylon, and at 133g (S size), we believe it’s one of the lightest three-layer rain jackets in the world with a double-zipper, despite its rather loose silhouette.

The double zipper allows for better ventilation

The double zipper allows it to be opened and closed from either the top or bottom for quick ventilation. This ensures you will stay comfortable in the ever-changing mountain conditions, including climbing ridges in high winds after a hard hike up.

Ultrasonic welding keeps water out

Standard rainwear prevents water from penetrating through the seams by applying seam tape to the sewing points from the back. But seam tape is not very durable, and water penetration due to wear is inevitable.

The UL Rain Jacket is sewn using the latest ultrasonic welding technology, which uses ultrasonic waves to melt the fabric and cloth together, reducing water penetration through the fabric’s joints.

Loose fit and good ventilation

We designed the Jacket to provide more room around the body and neck for efficient ventilation of body heat and moisture during movement.

Most lightweight waterproof shells of similar classes have a more form-fitting shape, but even though slightly heavier we kept the fit loose to allow for better ventilation and comfort.

Details

Adjusting the hood

There is a cord stopper on the inside of the hood fabric that adjusts the hood. Press the cord stopper and pull the cord under the hood to adjust.

Material

Two different materials

Both Pertex Shield Pro (PU Sosui) and Pertex Shield (PU Shinsui) are three-layer waterproof and breathable materials, but the structure of the membrane, characteristics, and moisture permeation mechanisms are completely different.

Pertex Shield Pro(PU Sosui)

Pertex Shield Pro is a polyurethane-based hydrophobic and microporous membrane. The “hydrophobic” material has high water repellency, and the “microporous” means that it has a number of very small holes (pores).

These pores are too small for liquid water (rain) to enter, but large enough for vapor (moisture from your body) to get out. Pertex Shield Pro effectively vents the moisture within the clothes from the pores, achieving superior breathability.

According to our test at our Yamatomichi Lab, Pertex Shield Pro prevents excessive temperature rise even during heavy exercise, while keeping a constant temperature when it rapidly gets cold. According to the information provided by the manufacturer, the Pro version is more durable than the regular Pertex Shield.

Pertex® Shield Pro

Material:
Pertex Shield Pro (100% NYLON)
Weight: 58g/㎡
Surface: 10d/10f x 10d/10f+30d, ripstop
Linning: 7d tricot
Water-repellent finish by C6 DWR

Specs:
Tear strength measured by JIS L 1096 D (Pendulum method)
Vertical: 1.0kg, Horizontal: 0.8kg

Tensile strength measured by JIS L 1096 A (Strip method)
Vertical: 27kg, Horizontal: 19.8kg

Breathability measured by KES method
270 or more

Water-permeability tested by JIS L 1099 A-1
11280g/㎡/day (Our measured value)

Water-permeability tested by JIS L 1099 B-1
20000g/㎡/day (Catalog spec)

Water pressure resistance tested by JIS L 1092 B
20000mm (Catalog spec)
https://www.pertex.com/fabrics/shield-pro/

*The PU Sosui uses ultralight and thin microporous material, the Pertex Shield Pro. Vaseline, insect repellent, and ethanol-containing substances such as hair creams, cosmetics and sunscreens may stain the fabric. They may also hinder the water-permeability of the fabric. Visit here to remove the oil stains.

Pertex Shield(PU Shinsui)

The Pertex Shield uses a polyurethane-based hydrophilic and non-porous membrane. Though the membrane has no holes or pores, it has a strong affinity to water, allowing the water to sink into the membrane easily.

In other words, the membrane absorbs the moisture within the jacket and then allows it to evaporate. It works like a towel that absorbs water, and then dries by itself.

The greatest advantage of Pertex Shield is its lightweight: The membrane is non-porous, so the fabric can be extremely thin and light. Our experiment has shown that it quickly lowers the humidity within the clothes immediately after being worn, but the humidity will gradually increase after a while. For this reason, you may feel more humid compared with the Pertex Shield Pro material.

Pertex® Shield

Material:
Pertex Shield (100% NYLON)
Weight: 47g/㎡
Surface: 7d/5f x 7d/5f, ripstop
Linning: 7d tricot
Water repellent finish: C6 DWR

Specs:
Tear strength measured by JIS L 1096 D (Pendulum method)
Vertical: 0.8kg, Horizontal: 0.7kg

Tensile strength measured by JIS L 1096 A (Strip method)
Vertical: 22.8kg, Horizontal: 21.2kg

Breathability measured by KES method
270 or more

Water-permeability tested by JIS L 1099 A-1
5568g/㎡/day (Our measured value)

Water-permeability tested by JIS L 1099 B-1
20000g/㎡/day (Catalog spec)

Water pressure resistance tested by JIS L 1092 B
20000mm (Catalog spec)
https://www.pertex.com/fabrics/shield/

Categorization and Characteristics of Waterproof and Moisture Permeable Material

The materials of waterproof jackets are generally made of multiple layers of fabric, that is, a waterproof and moisture permeable membrane is sandwiched between a water repellent, durable surface layer and an absorbent lining next to the skin. The membranes are roughly categorized into two groups according to the waterproof and moisture permeability mechanism: The hydrophobic, microporous membranes, and hydrophilic, non-porous membranes.

The hydrophobic, microporous membranes have a number of very small holes (pores) that are too tiny for the liquid water (rain) to come through, while allowing the vapor (moisture from your body) to vent. They are made of water-repelling ePTFE (expanded polytetrafluoroethylene, AKA, Teflon) or hydrophobic polyurethane (PU).

The most common ePTFE material is the eVent, and Pertex Shield Pro that we adopted. Polartec NeoShell is also a good example of a hydrophobic PU membrane.

On the other hand, hydrophilic non-porous membranes have no pores, so they permeate the moisture by absorbing the vapor within the clothes and evaporating it outside. Pertex Shield that we use, HyVent Flyweight by The North Face, and dri1 by Norrona are all non-porous membranes.

Gore-Tex, the most famous waterproof and breathable material, has a hydrophobic and microporous membrane with a hydrophilic coating. The purpose of the coating is presumably to prevent the contamination that can hinder the membrane’s performance, but due to the coating, it is inferior to non-coated hydrophobic, microporous membranes in moisture permeability. That said, Gore-Tex has many variations and it is probable that each product has a different level of coating depending on the exact specifics of the material.

READ MORE

Test at the Yamatomichi Lab

We have conducted thorough research on rainwear over a year at our Yamatomichi Lab. The result is available online at the Yamatomichi Journal (Japanese only), full of independent research, experiments and new findings.

#1 土屋智哉(ハイカーズデポ)x 夏目彰(山と道)特別対談
レインウェアのメカニズムや使いこなしについてさまざまな論点が出されました。この対談で提示された疑問がそのままラボのリサーチテーマになっていったと言っても過言ではありません。

#2レインウェア・マーケット分析
市場に存在するレインウェアを多角的に分析し、利用シーンをもとに分類しました。超軽量レインウェアとウインドシェルが用途的に重複するのではという発見もありました。現在では古くなった製品も含まれていますが、この分類軸は未だ有効であると思います。

#3 透湿試験とメンブレンの解説
メカニズムと既存の試験方法について深掘りしました。「疎水性」「親水性」というキーワードが重要性をおびるとわかるのはこの後、実際の実験結果がこの両者で大きく異なることに気付いてからです。

#4 独自検査法による透湿性能試験
ムレた高湿条件での透湿性をはかるべくオリジナルの調査を実施しました。結果にバラツキはあったものの、疎水性素材の優秀さと、ゴアテックスの保温性というメリットが浮き彫りになりました。

#5 電子顕微鏡による組成解析
謎の多い各社の素材をハダカにすべく、電子顕微鏡でアプローチしました。これまでの仮説を深めることができました。

#6 これまでのまとめ
#1~#5までのまとめです。こちらを一読いただければこれまでの流れがわかるようになっています。

#7 同一試験による防水透湿素材の総合評価
レイン素材単体の総合的なレビューです。実験結果をもとに、「疎水性」「親水性」を軸として素材を整理しました。透湿性や保温性、軽量性を高次に満たす完璧な素材はありませんでしたが、総合点のよい高バランスの素材をいくつか特定することができました。

#8 レイヤリングのもたらす効果
レイン素材をレイヤリングした場合の効果をテストしました。メリノウールの優秀さと、速乾をうたっていても蒸れやすいという化繊の弱点が明らかになりました。山と道レインもレイヤリングにはメリノウールを強くおすすめします。

READ MORE

Size

推奨サイズ/Recommended Size

Unisex
Size XS S M L XL
体重/Weight
kg
42~53 51~61 59~69 67~78 76~85
胸囲/Chest
cm
78~84 80~88 84~95 92~102 100~110

製品サイズ/Product Size

Unisex
単位:cm
Size XS S M L XL
着丈/Length 69 74 76 77 79
身巾/Body Width 50 55 59 63 67
裾巾/Hem Width 49.5 54.5 58.5 62.5 66.5
裄丈/Neck to Sleeve 81 84.5 86.5 90 90.5
袖口巾/Sleeve Opening 9.7 10 10.2 10.5 10.7

Care Instructions

  • The UL Rain Jacket is our ultralight water-resistant rainwear made of ultrathin, water-permeable fabric. Please handle with care as it can be torn or ripped when rubbed against rocks or scratched by spiky branches.
  • The UL Rain Jacket is comfortable when you on the move in a relatively warm environment. However, it is less warm than normal water-resistant jackets or winter hard shells so we strongly recommend you wear a merino wool base layer to keep you warm especially when severe weather is to be expected.
  • In order to maximize the moisture-permeability of the UL Rain Jacket PU Sosui/Shinsui, after-use care is necessary. The performances of the membrane, facing and lining can be impaired by dirt, sweat, and skin oil, or other substances. Please follow the washing instruction of each product to properly wash, dry, and keep it clean. The use of rainwear-specific detergent is highly recommended.
  • We recommend the use of water repellent spray regularly to restore the water repellency of the fabric.
  • The PU Sosui uses ultralight and thin microporous material, the Pertex Shield Pro. Vaseline, insect repellent, and ethanol-containing substances such as hair creams, cosmetics and sunscreens may stain the fabric. They may also hinder the water-permeability of the fabric. Please visit the following link to remove the oil stains: 、山と道JOURNALS『山と道修理部通信#2 レインウェアの油脂汚れをきれいにする』
  • Because the Pertex Shield has a different moisture permeability mechanism, the PU Shinsui is not stained by Vaseline, etc.

Care Instructions

  • Machine wash, gentle at 30°C.
  • Use Rainwear-specific detergent if available.
  • Wash separately or use a laundry net bag.
  • Fasten the zipper before washing.
  • Tumble dry below 60°C.
  • Do not bleach and do not use fabric softener.
  • Iron on low, covered the pants with a cloth. Do not steam.
  • Do not dry-clean.

Payment

  • 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.

Delivery

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.

Repair

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.

BUY

MORE