Lacquered rosewood and polished stone, hand-built in Japan since the late 1970s, and rebuilt by the same hands.

Yoshiaki Sugano was born in 1907 into a family with a tradition of sword-making. He studied political science at Meiji University, boxed professionally for three years and, as Stereophile's obituary records, reportedly never lost a fight; he learned metallurgy repairing broken blades. After a short time at Ford he spent most of his career at Toyota, retiring as a domestic-sales executive at sixty. He began with an Ortofon cartridge, substituting his own parts, and worked on the Supex SD-900, which some regard as a Koetsu prototype. The company he founded in Chiba Prefecture in the late 1970s took its name from Hon'ami Koetsu, the seventeenth-century calligrapher, potter and lacquer artist whom Sugano admired and claimed as an ancestor. The first Koetsu cartridges reached the United States at $800, and reviews, The Absolute Sound's among them, brought more demand than Sugano, his wife and his daughter could meet.

The models that defined the house were in place by the 1990s: the Rosewood in Standard and Signature grades, Signature meaning samples selected for closer tolerances and matched coils; the aluminum-bodied Black; the Onyx, the first Koetsu built into stone; and the Urushi, lacquered rosewood, usually dated to about 1990. In the early 1990s Sugano's eldest son Fumihiko, who had apprenticed under his father, took over production, and in 1993 Arturo Manzano met him in Tokyo and became Koetsu's American importer. In 1998, with Musical Surroundings of Oakland distributing, Stereophile reviewed the Urushi at $4,000 and the Rosewood Signature Platinum at $5,500; the Rosewood Signature was $3,500 and the Onyx Platinum $7,500. Yoshiaki Sugano died in Chiba on January 20, 2002, a few months short of 95. Stig Bjorge of Lyra called him the master craftsman who created the genre of true high-end phono cartridges.

Fumihiko Sugano ran Koetsu for three decades, through a series of American distributors: Koetsu USA in Chicago from about 2008, Pelotone around 2014, MoFi Distribution from about 2020. The stone line grew under him, with the Jade, Coralstone, Blue Lace, Tiger Eye and Azule joining the Onyx; the Blue Lace Onyx with a diamond cantilever reached $20,000 to $24,000 by 2009, and Koetsu was among the first cartridge makers to pass the $10,000 and then the $20,000 mark. The Urushi family grew to five finishes, all wound with silver-clad wire by 2022, and the Koetsu step-up transformer was reissued that year at $4,995. Fumihiko Sugano died in 2023 at 82. There was no third generation of the family to take over, and the Suganos chose to close the company rather than sell it to an outside buyer: staff dispersed, supplier contracts lapsed, and production stopped.

What came back was the old Koetsu under new ownership. Manzano, who had distributed the brand since 1993 through what became AXISS Audio, formed Analog2Fidelity in Gardena, California, and in May 2024 announced a worldwide service to rebuild every Koetsu ever made, using the original craftsmen. He then bought the name and assets, rehired the craftsmen, signed new contracts with the parts suppliers, and at AXPONA in April 2025 relaunched the brand with the Urushi Vermillion, Urushi Wajima and Rosewood Signature. The cartridges are built in Japan by master craftsman Ogura-san, who has made Koetsus since 1984 under both Suganos, with the supply team of Dai-Ichi Shoji; AXISS Audio of Nashville became North American distributor on May 1, 2025, and stone bodies returned in 2026 with a new Onyx Platinum at $15,495. Koetsu calls this not a revival but a continuation. Pearl Audio carries the current line in Portland.