I Sleep Hot. Nothing Can Beat Muji’s $9 Trunks.

Over time, I’ve noticed a few particularly well-designed details in the cut and construction that elevate these trunks above anything else in their price bracket (and even above some pairs that cost two or three times what these do).

I find the fit generous without being baggy. The inseam is just long enough to keep me well-covered around the house (for modesty), and the legs are cut wide enough that the shorts don’t pull or twist when I move my body or roll around at night. The trunks’ fit allows you to wear them as you might wear actual pajamas, whether you’re lounging around the house or briefly stepping out to pick up the mail.

The most notable feature is the three-panel construction. Most cheaper boxers have a two-panel construction, with a seam running down the center back, but Muji’s trunks are cut from three panels. This type of construction is usually seen only on more expensive trunks; in addition to eliminating the uncomfortable rear seam, it creates a more three-dimensional seat to better accommodate your butt and keeps the trunks from riding up.

They also have a strip of fabric covering the interior crotch seam, also for comfort. All of these construction details add extra steps and time to the manufacturing process, but they produce a pair of boxers that look and feel like so much more than a pair of boxers. Everything about these trunks is designed for comfort and lounging.

But what really made me fall in love with these trunks is the waistband. I never thought I could ever be moved to care about the waistband on a pair of boxers. And then I tried these.

Muji’s boxers are the only ones I’ve ever seen that have an explicit mention of a reduced-tightness waistband in their product description. It is indeed the most comfortable waistband I’ve ever worn: It provides enough resistance to keep the trunks in place but has such a light touch that I never feel any actual pressure.

Cynically, I suspect that Muji used a cheap waistband and is marketing that decision as a feature rather than a bug. But in this case, I also believe that cheapness is a virtue; the most expensive boxers I’ve owned have covered waistbands with a strong elastic, and the result is infinitely less comfortable than the terry loops on Muji’s low-resistance exposed waistband.

The comfortable waistband, along with the crisp, breathable fabric, makes these boxers feel airy and laidback in a way that mimics the leisure and aesthetic purposefulness of real pajamas. I never feel like I am using underwear for off-label purposes.

A nice-to-have would be the addition of a button at the fly, but its absence isn’t remotely a dealbreaker.