World of Jamaican Music

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An illustrated map of the creators of Jamaican music and how they are connected.

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Okuda Hiroko

Electronic instrument developer. Dancehall

Active
1980-2025
Sunrise
Nagasaki, Japan

Okuda Hiroko is the Japanese instrument developer who wrote the two-bar pattern that became the Sleng Teng riddim. She joined Casio in 1980 straight out of music college, as the company's first female developer and its first employee with a music degree, at the point when Casio was moving from calculators and watches into electronic instruments.

She had written one of the first Japanese graduate theses on reggae, and the year before she was hired she went to several dates of Bob Marley's only Japanese tour. One of her first assignments was the preset rhythms for the Casiotone MT-40, released in 1981. Writing a preset then meant converting a score into code, burning the code onto a ROM, and inserting the chip into a dedicated machine before anyone could hear what had been written. Among the patterns she wrote was one labeled rock, which cannot be used at a rock tempo.

In 1985 Noel Davey, who could not afford a Yamaha DX7, built a track on an MT-40 with Wayne Smith using that preset; it was slowed and reworked at King Jammy's studio and released, with Smith's vocal, as "Under Mi Sleng Teng." Okuda knew nothing about any of this until August 1986, when she read an article in Japan's Music Magazine describing the flood of Jamaican records being cut on a Casio preset. Several hundred versions have been made since. Casio later reinstated the pattern on its SA-76 keyboard, under the name MT40 Riddim.

She said nothing publicly for nearly forty years. Her account first appeared in a Nippon.com interview in early 2022, was carried by the BBC and the wire services, and has since had her recognized by strangers at trade fairs. She described the experience as putting a love letter in a bottle and having it wash up on the far side of the ocean. She retired from Casio on July 20, 2025, after nearly forty-five years, and has never been to Jamaica.

Last updated October 23, 2026

Connections

Notes

  1. "'Sleng Teng' Riddim Creator Okuda Hiroko Retires from Casio, Looks to the Future," Nippon.com, September 3, 2025, https://www.nippon.com/en/japan-topics/g02532/. Casio launched its first keyboard in January 1980, and "Okuda joined the company three months later, as a new hire straight out of music college." Yukinori Hashino, "Okuda Hiroko: The Casio Employee Behind the 'Sleng Teng' Riddim that Revolutionized Reggae," Nippon.com, February 1, 2022, https://www.nippon.com/en/japan-topics/g02027/.
  2. "Even my graduation thesis was on reggae." Hashino, "Okuda Hiroko." The claim that it was among the first such theses in Japan is not in the sources read.
  3. Hashino, "Okuda Hiroko."
  4. "It was necessary to convert a musical score into code, record the code onto an ROM, and then inset [sic] the memory into a specialized machine." Hashino, "Okuda Hiroko."
  5. Wikipedia says the preset is usable only when the tempo is turned down to the reggae range. "Okuda Hiroko," Wikipedia, accessed October 4, 2026, https://en.wikipedia.org/wiki/Okuda_Hiroko.
  6. On the DX7 and the MT-40: "Like a Human Flood: Attempting to Uncover the Real Sleng Teng Story," The Quietus, February 23, 2025, https://thequietus.com/opinion-and-essays/anniversary/wayne-smith-sleng-teng-riddim-40/. The Rough Guide says the rhythm "was then slowed down and re-recorded by Asher at Jammy's studio," while Bradley quotes Bobby Digital on the studio crew slowing it. Steve Barrow and Peter Dalton, The Rough Guide to Reggae, 3rd ed. (London: Rough Guides, 2004), 295. Lloyd Bradley, This Is Reggae Music: The Story of Jamaica's Music (New York: Grove Press, 2001), 522-23.
  7. The article in the August 1986 Music Magazine was titled "The Sleng Teng Flood." Hashino, "Okuda Hiroko."
  8. Nippon.com puts the number at "as many as 450 different songs." Hashino, "Okuda Hiroko."
  9. The 2022 article notes that the "MT-40 riddim" is installed in the SA-76. Hashino, "Okuda Hiroko."
  10. "'Sleng Teng' Riddim Creator Okuda Hiroko Retires." She describes approaches at trade fairs and being surrounded at the 2022 NAMM show; the BBC and Associated Press followed up the 2022 article.
  11. "'Sleng Teng' Riddim Creator Okuda Hiroko Retires."
  12. "On July 20 this year, Okuda retired from Casio after nearly 45 years"; "I have still never managed to get to Jamaica!" "'Sleng Teng' Riddim Creator Okuda Hiroko Retires."

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