One of Africa's most traditional instruments, the thumb piano, may look a little out of place in the hands of Sakaki Mango, a Japanese musician who has adopted it as his own.

Over the last decade, Mango has become known in his native Japan for mixing the sound of the traditional hand-held metal and wood instrument with songs he composes and sings in Japanese.

The result is a rare and quirky fusion, often frenetic, sometime touching, that intrigues -- and at times puzzles -- traditional players of the thumb piano, also known as a lamellophone.

"It's a very special instrument," said Mango, 37, and one that has won him "world music" awards in Japan for his three albums released in 2005, 2008 and 2011 -- a modest success in a country that otherwise idolises popstars but one that allows him to "make a decent living," said his manager Nicolas Ribalet.

The musician's fascination with Africa started as a teenager when he came face to face with an African for the first time, having previously seen black faces only on television.

He decided to study Swahili in Osaka before setting off, rucksack on back, for the Tanzanian bush where he discovered the pianos in local villages.

Part of Africa's musical heritage, thumb pianos have been used over the ages to celebrate marriages, to entertain when travelling or shepherding flocks and in rituals to invoke ancestral spirits.

Mango, 37, was "initially attracted to the religious aspect" of the instrument, Ribalet said, but later focused on developing his own sound as an artist.

He honed his skills under two prestigious African teachers - Galikai Tillicoti and the late Hukwe Ubi Zawose, who was lead player of the limba, the Tanzanian version of the thumb piano, at the Tanzanian National Theatre.

But Mango noted that traditional "players are always changing the tune until it fits their voice," so he did the same. He often sings in the dialect of his native island of Kyushu in southern Japan to "stay connected with my roots".

"It is my mother tongue, this accent is very melodic and easy for me, most of the people don't speak standard Japanese there," he said. "I am not African, and I want to put something Japanese in" the music.

-- 'Not making African music' --

One moving composition entitled "Small" was written specially for the victims of the tsunami-sparked nuclear disaster at Fukushima last year.

Mango, whose thumb piano is hooked up to an amplifier, makes an annual tour in Africa with his group, comprised of a bassist and a percussionist.

Each country has a different name for the instrument -- a mbira in Zimbabwe, a deza in South AFrica, a limba in Tanzania, a likembe in Congo and a timbili in Cameroon-- but the principle is always the same.

It has a row of strips, usually metal but sometimes fiber, laid across a kind of box. Unlike a piano, notes are not laid out in scales but arranged on both sides of the instrument so all notes can be played with each thumb, producing a rich, resonating sound.

Though Mango often draws wild applause, as at a recent festival in Swaziland, African listeners are still surprised to find a Japanese man on stage, dressed in African prints and playing such an African instrument.

Some are puzzled about his fusion style, like Zimbabwe's high priestess of the mbira, 66-year-old Stella Chiweshe.

"I don't find any sound like our mbira should sound. He composes his own sound. I cannot say it is bad, but this is not something I would encourage," she told AFP by telephone from Berlin, where she is now based.

For Chiweshe, the mbira "is a healing instrument". It's "our sacred instrument, we respect it, all the sounds are songs left by our ancestors" and each song brings down the spirits.

"It is not the ping ping of the instrument that brings down the spirits, it goes deeper than we know," she said.

But Mango's manager says such comments don't worry him. He is not trying to upstage traditional players and "doesn't pretend to be a mbira specialist. He loves the sonority but he knows he is not making African music," said Ribalet.