Unlike the recorder, where the air is channelled through a shaped mouthpiece, these Japanese shakuhachis depend on the player's skill in directing a thin jet of air, which means that it can take months before novices can produce a note. Shakuhachi means "1.8": one shaku (a traditional unit of measure) plus eight (hachi) tenths of a shaku. And to confuse things further, these flutes come in many sizes: with just five finger holes, their range of pitch is small, so to play really low or high you have to resort to a bigger or smaller flute - just like the recorder.
But if the pitch range is limited, the variety within it is enormous. There are just 12 notes in the recorder's scale, but in the shakuhachi's the number of pitch gradations is infinite, depending on whether you blow harder or softer, and how much your finger covers the hole. You can play microtones, or "bend" the notes, or turn them into slides and swops; you can whisper on the edge of audibility.
Made from bamboo root, this flute is a magical thing - which is why the Japanese gave it religious significance. Arriving there from the Middle East - possibly Persia - it was taken up by 17th-century Buddhist beggar-monks, who tramped through the countryside with their trademark long hair and straw mats, piping as they went.
Known as the Monks of Emptiness, they believed that the true goal of life was to blow the one perfect note which would transport them into heaven. Hence the baskets over these players' heads: by cutting out ordinary reality, they aimed to "become a Buddha in one sound".
Strange? Well, an impressive number of Western musicians are now setting out on the long, hard shakuhachi road, and some - such as the American Ralph Samuelson, whose CD Offerings is available on the Music of the World label - become masters of the art.
Two years ago, a world shakuhachi festival in Boulder, Colorado, attracted 150 players from Japan and an equal number from elsewhere. Not so much an instrument, more a way of life. An idea whose time has come?