Akira Natsume: Yamatomichi founder
Hidenori Maehara: Yamatomichi HLC ambassador and group leader
Oji: Yamatomichi Kamakura manager and Yamatomichi HLC ambassador
Tsunoda Yuko: Yamatomichi Kamakura staff
George: Yamatomichi Kyoto staff, currently working in Kamakura
Oden: Yamatomichi Kamakura staff
Beyoncé: Yamatomichi Kamakura staff

Season and temperature matter when choosing a base layer, but they are only part of the equation. The Kamakura staff also consider how hard they expect to move, how much they sweat, how many days they will be out and whether they need warmth after the fabric gets wet.

Maehara chooses Chemical B for his highest-output trips and for journeys lasting longer than a month, when repeated friction could eventually wear holes in merino. For trips ranging from a few days to several weeks, however, he most often chooses 100% Light Merino. He finds it the most odor-resistant option and trusts its durability over those distances.

DF Mesh Merino occupies a narrower space in his system. He uses it when he expects to work harder than he would on a relaxed merino hike but does not need the full sweat-handling performance of Chemical B. Snow trips are one example: Chemical B for harder days, DF Mesh Merino when he wants a little more warmth.

Yuko also chooses DF Mesh Merino for demanding, multi-day hikes. She sweats heavily and is particularly sensitive to her stomach becoming cold. Chemical B dries quickly enough to keep that from happening on day hikes and overnighters, but she describes it as being right on the edge of her comfort zone.

“If I’m going to be walking hard and sweating every day for five days, I’ll choose DF Mesh Merino,” she said. “For three days or more, it gives me more peace of mind. If I’m moving more slowly, I might choose 100% Light Merino instead.”

Her decision changes with the distance, destination, season and sometimes simply her mood.

For Beyoncé, comfort can matter more than outright moisture performance. He chooses 100% Light Merino for long-distance hiking because he feels settled as soon as he puts it on.

“Chemical B or DF may handle sweat better, but I like merino enough to choose it anyway,” he said. “It is less about relying on it during hard activity and more about feeling that this is the layer I want to walk with.”

Chemical B comes out when he is moving hard in the Japanese Alps in midsummer and prioritizes fast drying. He is still working out where DF Mesh Merino belongs in his system.

Oji, by contrast, turns to DF Mesh Merino when bad weather is clearly on the way. Chemical B can feel cold in poor weather at elevation, while DF Mesh Merino retains more warmth when wet and dries faster than he initially expected. During a nine-day traverse of the Ishizuchi mountain range in almost continuous rain, he wore the same DF layer throughout.

“That trip gave me a lot of confidence in it,” he said.

He also considers season when thinking about odor. For a long trip through hot, low mountains in summer, he would be less likely to choose Chemical B. In the cooler conditions of spring and autumn, he has found that he can wear it comfortably for longer. DF remains his usual choice in the snow, although he has recently begun wearing the Active Pullover next to his skin and carrying DF as a backup.

George may use DF Mesh Merino more than anyone else in the group. He reaches for it whenever high exertion, large temperature swings or getting wet are part of the plan. He also sizes it differently: while his other base layers are size L, he wears DF in size M so that its moisture-management system sits closer to his skin. The fabric’s stretch keeps the tighter fit comfortable.

His usual range for DF is around 0°C to 10°C, but he also wore it on a December trip to Yakushima that ranged from 26°C to snow.

Oden sits at the other end of the spectrum. He sweats heavily and has worn Chemical B almost exclusively since it was released.

“It has made Japanese summers easier,” he said. “Sometimes it doesn’t feel wet at all, even though it is actually soaked when I touch it.”

That lack of awareness of the moisture—not merely its drying speed—is what makes the fabric work so well for him.

Most of the staff wear the 100% Light Merino Half Zip Hoody directly against the skin. Natsume, who normally wears a base layer beneath it, was surprised to find that Yuko was the only other person in the group who regularly layered something underneath.

For Maehara, it is the most versatile piece in the entire 100% Light Merino range. He wears it on its own from spring through summer, including in the Northern Alps. At elevation, long sleeves and a hood provide essential sun protection. Opening the half zip while wearing the hood allows air to flow up through the front without exposing his head and neck.

Yuko uses it more often in the low mountains outside the main summer season.

Oji does not wear it at all. The skin around his neck is sensitive, and contact with a hood can cause irritation. That exception is just as useful as the group’s enthusiasm: even a much-loved product is not the right choice for every body.

The Active Pullover overlaps with the 100% Light Merino Half Zip Hoody because both can serve as either a base layer or a midlayer. Among the Kamakura staff, however, the more revealing comparison was with a down jacket.

Maehara uses an Alpha Vest when he expects to keep the same layer on throughout the day. When he wants insulation that he can add and remove, he chooses the Active Pullover. He finds a single layer of Alpha Direct too drafty, while Primaloft Active offers a better balance of warmth, airflow and moisture management for his body.

Beyoncé previously carried a short-sleeve T-shirt, a shirt and a down jacket on long trails in the US, without much between them. The Active Pullover filled that gap and, on many three-season trips, replaced down entirely.

“If I put on a down jacket first thing in the morning, I have to take it off again after ten minutes of walking,” he said. “With the Active Pullover, I can wake up and start moving in it.”

At roughly 150 grams, he considers the warmth impressive compared with a down layer weighing 200 to 300 grams.

Oji wears the Active Pullover as his moving layer in the low mountains in winter. At camp, he adds the UL All-weather Jacket and needs little else. George has used a similar combination throughout winter and now rarely sees a need for down on his own trips.

The staff also find the Active Pullover less prone to odor than they expected from a synthetic layer. Natsume believes that its ability to lift and disperse sweat allows it to dry before bacteria can multiply. He cautioned that it may behave differently beneath a layer that prevents that moisture from escaping.

The Active Pullover’s open structure makes it especially effective beneath a shell. Oji used the combination while moving through severe cold in Iceland and again in wet conditions in the Northern Alps.

Maehara finds the UL All-weather Jacket less comfortable directly against bare skin. Moisture can collect against the fabric, causing it to cling and reducing its ability to breathe. A long-sleeve layer underneath creates space and improves comfort. Yuko takes a similar approach: when wearing the jacket over a short-sleeve top, she adds Light Alpha Arm Sleeves to keep the shell away from her bare arms.

With the Kami Shirt joining the UL Shirt, Merino Shirt and Bamboo Shirt, choosing a Yamatomichi trail shirt has become more nuanced. Each material manages wind, heat and moisture differently—and the staff do not always agree on how those differences feel.

Maehara chooses according to both destination and mood. In the high mountains in summer, he often wears the Merino Shirt because it breathes well, resists odor and remains comfortable enough to leave on all day. He uses the UL Shirt when he expects to remove the layer at times or wants it to function more like a wind shell. The Bamboo Shirt comes out in cooler weather when he needs additional warmth.

He thinks of the Kami Shirt as something closer to a base layer—a “one-and-a-half layer.” The first time he used it, in the Tanzawa mountains in December, he wore it over a base layer and beneath a wind shell.

The difference between the Kami Shirt and UL Shirt can be subtle, he said, and changes noticeably depending on whether the air is still or moving. The Kami Shirt absorbs moisture, while the UL Shirt does not, allowing the polyester to remain smooth and separate from the skin.

Oji has almost the opposite experience at elevation. The Kami Shirt keeps his skin so dry that wind can make him feel cold. The slight humidity he feels inside the UL Shirt, on the other hand, can provide welcome warmth. For that reason, he prefers the UL Shirt in the high mountains when he wants both airflow and some protection from wind.

He reserves the Kami Shirt for lower mountains and days when he is not pushing the pace too hard. For fastpacking, he often chooses the Merino Short Sleeve Shirt. It allows him to move hard without carrying a change of clothes, resists odor well enough to wear throughout the trip and protects his shoulders from backpack straps better than a tank top. The short sleeves also suit his personal style.

The Bamboo Shirt is for slower hikes with other people in late autumn or early spring.

George arrived at the Merino Short Sleeve Shirt for similar reasons. He previously used a long-sleeve merino shirt in the Alps, but taking it on and off made layering cumbersome. Once removed, it was bulky and slow to dry. Switching to short sleeves gave him the sun protection he needed across the shoulders without the repeated clothing changes, and he has now used the same approach for two years.

“The idea was to choose short sleeves so I wouldn’t have to take the shirt off,” he said.

Yuko often carries the UL Shirt in the Alps precisely because she does not expect to wear it for long. She runs hot, so it usually stays in her backpack except during cold starts or strong wind. If sustained bad weather is forecast, she chooses a long-sleeve Merino Shirt instead. It gives her some warmth without trapping too much moisture.

At lower elevations in summer, she often wears the Merino Short Sleeve Shirt over a DF Mesh Merino or 100% Light Merino sleeveless base layer. Opening the front allows air to move through, while the odor resistance means she can complete a trip without carrying a spare shirt.

Beyoncé prefers long sleeves. Shirts allow him to adjust ventilation while adapting to shifts in temperature, and he values the additional sun protection. Since becoming a parent, he has also begun taking more relaxed hikes. For slower days in the low mountains in April, May and October, he often chooses the Bamboo Shirt.

For longer, harder days in the high mountains in summer, he chooses the Kami Shirt. On a trip through the Southern Alps, he felt that it managed the moisture leaving his skin before he was even conscious of sweating. The fabric remained comfortable, dried quickly and did not collect sweat around the rolled-up sleeves.

“When I reach a hut, I take it off, hang it up and put it back on again,” he said. “The Kami Shirt is what lets me stay comfortable throughout the day.”

Oden was initially nervous about how thin the Kami Shirt felt. On his first trip with it, wet bamboo grass soaked the fabric soon after rain. The next time he looked, it was already dry—even though the sky was overcast and the humidity was high. Later, when the shirt became saturated with sweat, it still avoided the unpleasant cling he expected.

The experience made him wonder whether the Kami Shirt could eventually replace the UL Shirt in his summer system. For now, however, the UL Shirt remains the easiest option for him to trust anywhere, because he can immediately understand how it fits into his layering. The Bamboo Shirt remains his choice for cool-season low mountains and brushy fishing trips.

If Natsume had to choose only one trail shirt for a long trip, he would take the UL Shirt. It adapts to the widest range of situations, provides warmth and blocks wind. In hot summer conditions, he prefers the feel of the Kami Shirt. The Merino Shirt offers a particular kind of comfort in the breezy high mountains that the other fabrics cannot reproduce, while the Bamboo Shirt comes into its own during the cooler days of late autumn.

The discussion did not produce one definitive answer. Instead, it showed how differently hikers experience the same fabrics. A layer that feels cool and dry to one person may feel cold to another. A shirt that one hiker carries only for wind may stay on someone else all day.

The conversation finished with a short detour into the 5-Pocket Shorts.

Maehara has worn the same 2018 Nomad pair for nine years, including on a long trail in New Zealand, and they are still in active use. For him, their longevity is the clearest expression of the product.

Oji described the 5-Pocket Shorts as the most balanced option in Yamatomichi’s bottoms range: light, fast-drying and durable enough for regular use from daily life to the low mountains. That balance makes them particularly easy to recommend to hikers buying their first piece of ultralight clothing.

Yuko highlighted the structured fabric. Although it looks as though it might cling, its shape and firmness keep it away from the skin.

The team agreed that the shorts deserved a full comparison of their own.

The staff left the conversation with new ideas about products they already knew well. More importantly, they were reminded that their own experience represents only one kind of hiker.

Yuko noted that it is easy to explain a product through the lens of her own body, but much harder to advise someone with a different metabolism or sensitivity. Hearing how other staff use the same layers gave her more ways to help customers find what works for them.

Oji felt that these conversations had always happened informally among staff, but rarely been recorded. Building that shared record could deepen the team’s understanding over time.

There is no single correct way to choose what to wear. The value lies in understanding your body, the conditions ahead and the compromises each piece of gear asks you to make.

The next PRODUCT FOCUS roundtable continues the same conversation with the staff of Yamatomichi Kyoto.