KGR Harmony is a Japanese effects pedal company founded in 2019 by Keijiro Fukushima, an electronic engineering graduate of Tokyo Denki University who spent over a decade researching how enclosure materials affect guitar tone. The brand is based in Iwate Prefecture, Japan, where pedals are hand-built in partnership with Oitomi Ironworks, a cast iron forge operating since 1848. Each enclosure is produced using Nanbu-tekki, a centuries-old regional ironcasting technique that gives the pedals their distinctive textured surfaces and substantial weight.

The lineup centers on boutique guitar effects housed in those cast iron shells, including the ARARE overdrive with 3-band EQ, the IRON808 overdrive, the KUROFUNE Ram's Head-style fuzz, the SHIZUKU boost, the OROSHI compressor, and the KUROHAKO buffer. The company also produces the Iwayado amp cabinet as a custom-build offering. KGR Harmony USA, the brand's North American arm, was established in 2023 in Tacoma, Washington to handle distribution outside Japan.

KGR Harmony has produced limited-edition Nanbu-tekki collaborations with EarthQuaker Devices and Lollar Pickups, pairing the Iwate ironwork tradition with established American pedal and pickup designs.

KGR Harmony has 1 product cataloged on Equipboard, including Overdrive Effects Pedals.