102g (Size M)
111g (Size L)
123g (Size XL)
- Introduction
- Versatile thermals for active hikers
- Product story
- Is it worth the weight?
- Layering
- Light Alpha Tights + pants
- At camp
- Light Alpha Tights + shorts
- Form and function
- Thermal comparison
- Excellent breathability
- Fast-drying
- Lighter than down pants
- Details
- Material
- Polartec Alpha Direct
- Size guide
- Notes before use
- About shedding
- Instructions
- Care instructions
- How to restore loft
- Repair
Introduction
Versatile thermals for active hikers
Made from Polartec Alpha Direct, the Light Alpha Tights are ultralight, breathable, and built for versatility.
This active insulation layer provides reliable warmth even in cold or inactive moments. Worn under long pants, they help retain heat in chilly conditions, and thanks to their quick-drying nature, they stay warm even when wet. Lighter than down pants, they also make excellent sleepwear at camp.
They pair especially well with our Light 5-Pocket Pants—highly recommended for the ultimate layering system.
Due to the nature of the fabric, some fiber shedding may occur with wear and washing.
For more details, please see “About Shedding”.
Product story
Is it worth the weight?
The inspiration for Light Alpha Tights came three years ago when I went hiking with Takeshi Azuma (a.k.a. Denki), the owner of Yamashokuon in Kyoto, on Mt. Ishizuchi.
It was a cold day at camp and we were talking about pants choices for the winter. At Yamatomichi, it’s either the Merino 5-Pocket Pants or Winter Hike Pants. I was wearing the Merino 5-Pocket Pants that day, and was fully satisfied with the warmth and functionality of the merino wool. Then, Denki said to me that he wanted to wear the Light 5-Pocket Pants in winter.
Makoto Fujiyama, wearing the 2024 version Light Gray color.
Surprised, I asked: “Why wear the thin Light 5-Pocket Pants in winter?” But when you come to think of it the Light 5-Pocket Pants are very comfortable because of how light they are. He wished to experience that comfort in winter as well, and this led to the conversation of combining the Light 5-Pocket Pants with thermal tights or Polartec’s Alpha Direct, the insulation material used for the lining of the Alpha Anorak. Eager to see this take shape, I immediately began to create a sample of Light 5-Pocket Pants lined with Alpha Direct after returning from the trip.
However, when I actually tried it on, I found that the product was not as attractive as I imagined. The differences in the two fabrics made the final product a little stiff. Therefore, I decided to stop using the Light 5-Pocket Pants and to create tights from Alpha Direct alone. By doing so, I thought that the final product would be more flexible and versatile.
Since thicker tights make it difficult to wear bottoms over them, I decided to make a prototype using a thinner type of Alpha Direct, used for the Light Alpha Vest/Jacket. When I tried on the finished prototype, it was warm when standing still, but when moving, it allowed air to pass through and made it feel as if I wasn’t wearing anything at all.
The idea was interesting, but I thought that it wasn’t quite attractive enough to be a Yamatomichi product. As an ultralight advocate, I knew that even a single gram of weight reduction would lead to greater comfort on the trail, and I wondered at the time if these tights were worth bringing on trips.
However, after hearing the rave reviews from the ambassadors of HLC Yamatomichi and friends that tested the prototype, I decided to give it a chance and the prototype entered the second year of testing. The more I tested, the more I realized how useful these tights are.
Naomi Kazma, wearing the Bright Orange color.
The appeal of Light Alpha Tights is the weight to warmth ratio, and the fact that they can be used in active situations. I don’t bring down pants unless I really have to, because they are heavy and I only seem to use them at camp. They are very functional for the weight they cost you. If I’m cold, I can just wrap myself in my sleeping bag. They never make my gear list. However, the Light Alpha Tights are light at 96g (Size S), and when worn alone or in combination with shorts, they feel cool as if you are not wearing anything at all when you move, but if you wear windproof long pants on top of them, they instantly show their warmth and still have the breathability to keep you comfortable. They are also warmer than ordinary tights when worn inside a shrug at bedtime. Its lightness and versatility made me feel that it was definitely worth bringing along.
And by combining it with the Light 5-Pocket Pants, your winter bottom that tends to be heavy becomes light but warm. I used to think that the Merino 5-Pocket Pants were my only choice in winter unless it was a snow-covered mountain, but this lightness was appealing to me as I use them every day.
You can wear them as tights under your pants or shorts, or wear them over your bottoms like down pants. I carry it with me on a daily basis. They come in handy when your shorts are a little too cold for you at work.
The excellent air-permeability makes it a good choice to combine with shorts for trail running or fastpacking in colder weather. Some say they used them as tights for skiing. I think there are many advantages to this piece of gear depending on the purpose of use. How would you use it? What do you feel is good about this tool? I’m looking forward to hearing your thoughts after the product is in your hands.
Sep. 2021
Layering
Light Alpha Tights + pants
Pair the lightweight yet insulating Light Alpha Tights with thin long pants to stay warm and agile, even during the colder months when layering tends to add bulk.
They’re especially well-suited to our Light 5-Pocket Pants. Together, the two pieces weigh just 245g—significantly lighter than our winter-ready Merino 5-Pocket Pants, which come in at 423g.
At camp
Highly breathable and soft against the skin, the Light Alpha Tights are perfect for staying warm at camp or sleeping in. The relaxed fit—looser than typical tights—also makes them easy to wear over shorts.
While they’re not as warm as down pants, they weigh just 96g (Size S), making them an easy, lightweight layer to bring along on any trip.
Light Alpha Tights + shorts
Ideal for those who like to stay in shorts—even when it’s cold.
Made with a lightweight (85g/m²) Polartec Alpha Direct, the Light Alpha Tights offer exceptional breathability. Paired with shorts, they let air flow freely as you move—so you stay cool while active—but still provide warmth when you stop. They dry quickly, wick away sweat efficiently, and even when wet, they keep you warm much like synthetic insulation.
Form and function
Thermal comparison
The 85g/m² Polartec Alpha Direct used in the Light Alpha Tights can’t match 1000FP down, but it’s warmer than wool and works not only as an active layer, but also as an effective insulation piece.
Comparative test:
A comparison of the insulation performance of 1000FP down and insulation materials used in active insulation layers on the market.
- Insulation performance is based on Yamatomichi’s in-house testing following JIS L 1096 A method. Thermal insulation is measured by the amount of energy required for a heating element to maintain temperature. Maximum value is 100%.
- Fabric weights for Polartec and Primaloft are based on manufacturer data; all others are measured by Yamatomichi. 1000FP down includes 7-denier nylon shell and lining.
Excellent breathability
By using highly breathable Polartec Alpha Direct with no outer fabric, ventilation is further enhanced. It retains warmth while allowing heat and moisture to escape, keeping you comfortable during movement.
Comparative test
The below chart compares the breathability of middle layer products*:
*Measured by JIS 1096 A (Frazier method), in Yamatomichi in-house test.
Fast-drying
Dries quickly even when wet with sweat.
Comparison test
The below chart compares the fast-drying performance of middle layer products*. It is shown that Alpha Direct is not as fast-dry as the extremely fast-drying Shadow Rip (UL Shirt), but the moisture content after spin-dry is much lower than that of wool and other fabrics, and even when wet, it dries quickly if lightly wrung out or worn for some time:
*Tested by Yamatomichi. Compared the difference of the water content after completely wet and 15 minutes of spin-dry. The larger the value, the higher the moisture content, meaning slower drying.
Lighter than down pants
Lighter than typical lightweight wool tights or down pants. Because they are so light, you can pack them without hesitation even in situations where you are not sure whether to bring an insulating layer or not.
The weight is the average of the total of each size.
Details
The waistband features a flat elastic band sewn with stretch thread for comfort and flexibility. To help you quickly tell front from back, our logo is placed at the front.
A three-needle coverstitch is used on the inner leg seams to minimize bulk and enhance comfort.
The hem features a stretch knit binding that gently hugs the ankle for a secure fit.
If the washing label causes discomfort, you can remove it by carefully cutting the threads that attach it.
Material
Polartec Alpha Direct
Natural and synthetic down trap heat by sealing in warm air, but they also tend to trap moisture, leading to overheating and dampness.
Polartec Alpha Direct, on the other hand, was developed as an active insulation. It retains warmth while allowing air and moisture to pass through, helping regulate body temperature during high-output movement and preventing overheating or chill from sweat.
It’s also treated with Polygiene®, a low-concentration silver ion finish that safely inhibits the growth of bacteria, providing long-lasting odor control well beyond the lifespan of typical garments.
- Exceptional balance of breathability and warmth
- Ultralight and highly packable
- Near-permanent odor control with Polygiene® treatment
Similar to fleece, but with a longer, more open pile.
Size guide
Size chart
| Size | S | M | L | XL |
|---|---|---|---|---|
| Height (cm) | 150~167 | 165~175 | 173~180 | 178~185 |
| Weight (kg) | 42~60 | 57~67 | 64~77 | 74~85 |
| Chest (cm) | 60~80 | 74~84 | 82~92 | 90~94 |
Product dimensions
※1: The listed waist size is measured without stretching the elastic waistband
※2: The listed hip size is measured at the widest point when laid flat.
Unit: cm
| Size | S | M | L | XL |
|---|---|---|---|---|
| Pants length | 100.5 | 103 | 106.5 | 109 |
| Inseam | 77 | 79 | 82 | 84 |
| Waist | 64 | 67 | 70 | 74 |
| Hip | 54.5 | 57 | 59.5 | 62 |
| Hemline | 11.5 | 12 | 12.5 | 13 |
*Actual measurements may vary slightly. Sizes may change over time as the fabric can shrink with wear.
Fitting
Shigeru 172cm 60kg
Size L (Black)
Shigeru 172cm 60kg
Size L (Black)
Kanade 161cm-51kg
Size S (Glacier White)
Kanade 161cm-51kg
Size S (Glacier White)
Ichiro 170cm-56kg
Size S (Glacier White)
Ichiro 170cm-56kg
Size M (Glacier White)
Matsu 169cm-69kg
Size M (Black)
Matsu 169cm-69kg
Size L (Black)
Ippei 172cm-62kg
Size M (Black)
Ippei 172cm-62kg
Size L (Black)
Pony 173cm-76kg
Size L (Black)
Kim 175cm-68kg
Size M (Glacier White)
Kim 175cm-68kg
Size L (Glacier White)
Nacho 180cm-68kg
Size L (Glacier White)
Nacho 180cm-68kg
Size XL (Glacier White)
Ichiro 170cm-56kg
Size S (Glacier White)
Ichiro 170cm-56kg
Size M (Glacier White)
Matsu 169cm-69kg
Size M (Black)
Matsu 169cm-69kg
Size L (Black)
Ippei 172cm-62kg
Size M (Black)
Ippei 172cm-62kg
Size L (Black)
Pony 173cm-76kg
Size L (Black)
Kim 175cm-68kg
Size M (Glacier White)
Kim 175cm-68kg
Size L (Glacier White)
Nacho 180cm-68kg
Size L (Glacier White)
Nacho 180cm-68kg
Size XL (Glacier White)
Natsumi 152cm-43kg
Size S (Black)
Rin 156cm-49kg
Size S (Black)
Eriko 158cm-47kg
Size S (Black)
Kanade 161cm-51kg
Size S (Glacier White)
Kanade 161cm-51kg
Size M (Glacier White)
Shiori 167cm-55kg
Size S (Black)
Shiori 167cm-55kg
Size M (Black)
Hikaru 165cm-59kg
Size M (Glacier White)
Hikaru 165cm-59kg
Size L (Glacier White)
Yumiko 170cm-60kg
Size M (Glacier White)
Yumiko 170cm-60kg
Size L (Glacier White)
Natsumi 152cm-43kg
Size S (Black)
Rin 156cm-49kg
Size S (Black)
Eriko 158cm-47kg
Size S (Black)
Kanade 161cm-51kg
Size S (Glacier White)
Kanade 161cm-51kg
Size M (Glacier White)
Shiori 167cm-55kg
Size S (Black)
Shiori 167cm-55kg
Size M (Black)
Hikaru 165cm-59kg
Size M (Glacier White)
Hikaru 165cm-59kg
Size L (Glacier White)
Yumiko 170cm-60kg
Size M (Glacier White)
Yumiko 170cm-60kg
Size L (Glacier White)
Notes before use
About shedding
Shedding may occur overtime with use and frequent washing. This is due to the structure of the loft where hairs are directly implanted into the mesh fabric.
Used 3 seasons
New
Instructions
Care instructions
- Machine wash, below at 30°C, Use neutral detergent.
- Wash separately or use a laundry net bag.
- Do not bleach. Do not use fabric softener.
- Dry flat in the shade to prevent stretching under its own weight.
- When using a dryer, use a low-temperature setting (60°C or lower).
- Do not dry-clean.
- Do not iron.
- If fluff is noticeable at the time of purchase, please wash once.
Care page
Visit our Care page for detailed washing, drying, and general care instructions.
How to restore loft
The lofted fibers used in Yamatomichi’s active insulation are lightweight, breathable, and provide comfortable warmth. However, with continued use, these fibers can become flattened, which may reduce warmth.
If this happens, gently brush the fibers in their natural direction using a metal stuffed-animal grooming brush. Our internal testing shows that this simple care method can help restore loft and improve warmth.
At YamatoMichi retail stores, we offer in-store brushing support, and staff can show you how to do it properly. If you’re unsure about caring for your item at home, feel free to ask us for help.
*This method helps restore loft to flattened fibers, but fibers lost through wear cannot be replaced.
The degree of warmth recovery will vary depending on the condition of the product.
Before Brushing
After Brushing
What You’ll Need
- A metal grooming brush for stuffed animals
How to Restore Loft
- Lay the area you want to revive as flat as possible.
- Gently brush the flattened fibers several times in one direction.
- Once the loft stands up again, you’re done.
Notes
- Avoid brushing too hard, as it may damage the fabric.
- Only brush when the fabric is completely dry.
- The degree of loft recovery will vary depending on the material and product.
Payment
- We only accept payment by credit card for orders from overseas.
- Bank transfer is available only to customers with a Japanese bank account.
- We accept the following credit cards: Visa, Mastercard, American Express, and JCB.
- To download your receipt, please click the link included in the dispatch notice email, which will be sent once your order has been shipped.
Delivery
- Order Confirmation will be sent after the order.
- The items will be dispatched within 5 days after the payment is confirmed.
- The dispatch notice will be sent by email as soon as the items are dispatched.
- The delivery may be delayed by unforeseeable reasons such as natural disasters and other logistics issues. We appreciate your patience and understanding.
- We cannot ship multiple orders in one package due to how our delivery system is currently set up.
- We will ship to regions in North America, Oceania, and Europe via DHL. For regions in Asia, the Middle East, Central and South America, Africa, we use EMS (International Express Mail Service) for shipping. We currently cannot ship to Russia due to Japanese postal regulations.
- Shipping fees and delivery times vary depending on the shipping destination as well as the size and weight of the items. To find out how much shipping will cost, please add all of your desired items to your cart and enter your shipping information, the exact amount will be shown.
Size exchange
Choosing the right size online can be difficult. To make your purchase easier, Yamatomichi offers a size exchange program for eligible items. To request a size exchange, please use our size exchange form here. Please review the conditions below before submitting your request.
- We only accept exchanges when the item is unused (except for fitting).
- If you would like to exchange your item for a different size, please contact us within seven days of receiving your order.
- Exchanges are available only for the same color in a different size.
- If your preferred size is out of stock, we may suggest a different color instead.
- If the product is no longer available, we may need to return the original item to you.
- All shipping costs are the responsibility of the customer.
- We will send the exchanged item after receiving payment for the return shipping cost via PayPal.
- Please note that some countries may charge customs duties depending on the value of the item.
- We are unable to advise on local customs regulations. Please contact your local customs office directly.
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.