The Casio MT‑40
The Toy Keyboard That Changed Reggae Forever
A Consumer Keyboard… That Sparked a Revolution
In 1981, Casio released a humble home keyboard—cheap, plastic, and portable. It had just 37 main keys and 15 smaller bass keys, a few rhythm presets, and a built-in speaker.
It wasn’t a synthesizer in the traditional sense.
Instead of generating tones from scratch, the MT‑40 played back pre-recorded sounds stored on “voice chips.” Think of it like a musical sketchpad made for beginners.
But one hidden preset, simply called “Rock,” would go on to shake the very foundation of reggae—and spark a digital revolution.
The Woman Behind the Preset
The now-famous preset was created in 1980 by Hiroko Okuda, a newly hired music engineer at Casio.
She had just graduated music school—her thesis? One of Japan’s first academic papers on reggae.
She wasn’t just experimenting—she was deeply immersed in reggae culture, even attending multiple Bob Marley shows during his only visit to Japan in 1979.
Assigned to develop drum rhythms for the MT‑40, Okuda composed the "Rock" preset. She didn’t know it at the time, but that loop—made quietly in a Casio office in Japan—would become one of the most sampled rhythms in music history.
She only learned about its influence in 1986, when she read an article titled “The Sleng Teng Flood” in Japan’s Music Magazine, describing how dozens of Jamaican producers were making tracks using her rhythm.
"I didn’t know. I was just doing my job. Then I saw it in a magazine: reggae had gone digital—with my rhythm."
– Hiroko Okuda
The Birth of Digital Reggae
In a small Kingston studio, Noel Davy discovered the preset and passed it to vocalist Wayne Smith, who then brought the beat to King Jammy.
What they created was historic:
“Under Mi Sleng Teng” (1985)
The first fully digital reggae riddim—powered entirely by a preset from a toy keyboard.
Minimal. Hypnotic. Synthetic. And it exploded.
Over 500 tracks were produced using this same pattern within months.
Digital Dancehall was born.
Note: "Unda mi sleng teng" is being under the influence of marijuana.
What Was Inside the MT‑40?
Despite its toy-like appearance, the MT‑40 packed some clever features:
9-Voice Polyphony: 8 notes from main keys + 1 bass note
22 Timbres: Assignable to 4 voice presets
Bass Section: One solid timbre—perfect for dubby lines
Built-In Drum Machine:
6 rhythms including Rock
Tempo knob + “fill” button for 16th-note kick/snare bursts
ROM-Based Sound: No synthesis—just sample playback from internal chips
It was built for fun, not for studios. But reggae has always thrived on flipping the unexpected.
Recreate the MT‑40 Sound Today
Sample Pack
Goldbaby MT‑40 – top-tier drum hits & loops https://www.goldbaby.co.nz/mt40.html
How Much Does a Real MT-40 Cost Now?
There’s on listed on Reverb.com for $500+ USD
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The MT‑40 wasn't built for the studio.
It wasn't meant for legends.
But reggae has always been about flipping the unexpected into the unforgettable.
Thanks to a fresh-out-of-school engineer in Japan and some Kingston ingenuity, this plastic keyboard defined the sound of a new generation.