ONI DENIM Frequently Asked Questions (Complete Guide)

What is ONI Denim?

A denim brand created independently by Mr. Masao Oishi, known for extremely rough, highly textured fabrics. In Japanese, the word “ONI” (demon) often describes something intense, powerful, or beyond normal limits—perfectly capturing the dramatic texture of ONI fabrics. With over 50 years of industry experience, Oishi-san developed iconic fabrics such as Secret, Bumpy, Asphalt, and Crushed Concrete. The brand has no official website or social media, yet became globally famous purely through its craftsmanship.

Where is ONI Denim made?

Every stage—yarn, weaving, dyeing, sewing—is 100% made in Japan. Oishi-san collaborates closely with various textile mills to produce low-tension, high-difficulty fabrics that few others can weave. His technical ability is considered irreplaceable in the Japanese denim industry.

When was ONI Denim founded?

ONI was founded a little over 20 years ago by Masao Oishi. Before establishing ONI, Oishi-san worked at Oishi Trading and was among the first employees of Levi’s Japan—making him a living piece of Japanese denim history. Related article: The true history of ONI Denim and the origins of Japanese jeans

Who makes ONI Denim?

Almost every fabric and fit is personally overseen by Oishi-san. He works directly with mills and is known for pushing the limits of old shuttle looms to create extreme textures and irregular yarn behavior. Each fabric reflects his unique design philosophy.

Why is ONI fabric fuzzier, rougher, and more neppy than other brands?

Because ONI uses specific cotton types combined with modified vintage shuttle looms designed to create dramatic irregularity. Oishi-san adjusts yarn twist, tension, and loom settings to intentionally produce intense slub, nep, and irregular surface expression.

What is the difference between ONI’s low-tension denim and standard denim?

Low-tension denim is softer, more flexible, and stretches noticeably within the first week of wear. Because the yarn is woven without high tension, the fabric has more air, more irregularity, and conforms to the body more naturally—resulting in quicker break-in and more visible stretching.

What is Secret Denim?

ONI’s most iconic 20oz heavyweight fabric—rough, tactile, and surprisingly comfortable. Despite its rugged surface, its low-tension weave makes it breathable and unexpectedly wearable.

What’s the difference between Secret, Bumpy, Asphalt, and Crushed Concrete?

Secret — 20oz, rough yet comfortable, ONI’s signature.
Bumpy — Vertical cascading texture with unique overdye effects.
Asphalt — 20oz with extremely dense nep and rugged surface, resembling asphalt.
Crushed Concrete — Between Secret and Asphalt, strong texture but only 15oz and suitable for all seasons.

How much does ONI Secret Denim stretch with wear?

Usually 1–2 inches in the waist. The low-tension weave allows yarns to relax quickly, especially within the first week.

Does ONI Denim stretch a lot?

Yes — ONI is among the most stretch-prone premium denim brands. The waist expands the most due to the loose weave structure.

How long does it take for ONI Denim to break in?

Noticeable in 2–3 days, fully comfortable after 1–2 weeks.

Should I size up or size down for ONI Denim?

Do not rely on tagged sizes. Always choose based on the flat measurement that fits you after stretching. Different brands follow different sizing systems. ONI stretches more than most. Reference guide: The ultimate tutorial to help you shop for the right size in jeans

Will ONI Denim shrink again after the first wash?

Very minimally. Even if it tightens slightly, it will stretch back within a few wears.

Why is ONI Denim more expensive than other brands?

Because producing low-tension denim is extremely difficult, unstable, and has a high fabric loss rate. For some fabrics like Asphalt Denim, loom loss can exceed 30% — dramatically increasing production cost.