INTENSE Japanese instrumental groups look set to be a regular feature at the Mosaic Music Festival. Last year, Toe performed. Last Friday, Toe's label mates at Machu Picchu, mouse on the keys, helped to kick off the festival with two sold-out sets.

Those unfamiliar with mouse on the keys may have been somewhat unprepared for the speed and breathless energy of the music. After all, an acoustic trio comprising two keyboards, a drum and an occasional trumpet isn't usually the sort of outfit to have more rhythmic intensity than a heavy metal band.

But when mouse on the keys kicked off the second set at 10.30pm with the first three tracks of its 2009 album, an anxious object, and the keyboard duet

complete nihilism segued explosively into spectres de mouse, jaws dropped.

Drummer Akira Kawasaki is a force of nature. His complex style is impressive enough, but the sheer speed at which his arms fly made one wonder not only how long he could keep up the pace, but how keyboardists Daisuke Niitome and Atsushi Kiyota could keep track of where they were in any particular piece.

Yet Kawasaki kept it up for more than an hour. And Niitome and Kiyota were whiplash tight, cutting off and coming in precisely where they were supposed to, with almost telepathic precision.

The band occasionally plays with either saxophonist Jun Nemoto or trumpeter Daisuke Sasaki, and the latter accompanied the core trio on its Singapore debut.

This meant that songs such as Seiren, which features Nemoto in the studio recording, sounded more dynamically varied live thanks both to Sasaki's distinctive phrasing and the timbre of his instrument, which he sometimes played with a mute.

mouse on the keys also sounds quite different on record because it's hard for most hi-fi sets to reproduce the visceral impact of the drums. So while keyboards are balanced more evenly with the drums on record, Kawasaki dominated the proceedings on Friday night - more than just musically.

Near the end of the second set, he abandoned the seat he'd kept to for most of the performance, ran around the Esplanade Recital Studio, and stood on his drum set while hollering at the top of his voice. Quite a character.

The band members took turns imploring the audience to buy merchandise. Niitome said that they needed to sell at least half their stocks of CDs and DVDs. "Otherwise we can't go home," he quipped, tongue firmly in cheek. "Airline fees very expensive."

The plea must have been at least partly successful because all the CD copies of an anxious object were sold out even before the start of the second set, and in spite of the $35 cost.

Perhaps fans didn't know that the same album costs $11.52 as an iTunes download. Or that both $20 EPs, Sezession and Machinic Phylum, also cost $3.99 and $1.99 on iTunes, respectively.

Perhaps fans simply didn't care.

Also, the second set had the sort of musical conviction that makes even newcomers happy to part with their cash.