A decade ago the Scottish International Children’s Theatre Festival was some tents in Inverleith Park, Edinburgh, with an “international” dimension that was hardly more than a token. Since then, a few things have happened.

There was a summer monsoon that proved this was one kind of camp that theatre could do without. The Scottish Arts Council moved in with a weighty Advancement grant. The City of Edinburgh upped its stake and the festival’s sponsors added to the cascade of money to the point where the new Bank of Scotland Children’s International Theatre Festival this week has been hosting quality companies from Denmark, Germany, Italy and the USA in studio theatres.

Edinburgh teachers again rushed to book up the festival. Director Tony Reekie admits that the benefits go mostly to Edinburgh children, though there have been school parties from as far as South Uist and the Skerries, and afterwards Theater Triebwerk from Germany will tour its Moby Dick from Kilmarnock to Invergordon.

For those with the Traverse and Lyceum theatres on their doorstep, the choice has been mouth-watering. From Denmark, a country which is to children’s theatre what Sweden is to furniture, has come Haiku. The performance is minimalist, elegant and resonant. The two performers in black, hardly speaking - she smiling a warm, secretive smile; he rubber-faced and elastic of body - live through a romance that lasts the four seasons of the year.

The audience (three to six years is the target group) come in to the sound of water, lulling them to silence, and he swims towards us, body horizontal, a powerful breast stroke, puffing and blowing and water in his eyes, with one foot on the ground, rather as I remember getting my first swimming badge.

It is a brillint mime and launches this pair of gifted and practised performers into 50 minutes of highly accomplished, evocative theatre in which conjuring, dance, clowning and miming swim together into a celebration of human affection and the natural world.

Spring is frogs, hopping unexpectedly and clambering, sprawling over one another; summer is butterflies fluttering round her head as he tries to net them; in autumn she is an apple tree he first harvests and then fells for a Yule log; in winter the stage turns to ice on which they first flounder but then skate on in elegant companionship, before the spring melt allows him to swim again.

Minute by minute, the art, almost the magic, of theatre fascinate the audience, whatever their age.

Catherine Wheels is a children’s theatre company that in its short life so far has enjoyed meteoric success, not least as the only Scottish company to play on Broadway. It brought to the festival Frankenstein, in a version by Tom McGrath that makes the eponymous doctor a woman, a device that adds post-natal rejection to the matrix of meanings that coalesce around this fable of created life.

Once the play gets past the body assembling scenes, where the production seems to want to pander to its young audience (aged 10 and over), a passion catches both Gill Robertson (the company director playing the doctor) and Lee Hart, who contributes a superbly modulated performance as the monster, growing from shambling incoherence to superhuman. Iain Johnstone again provides a passionate music track.

Even with eight other productions vying for attention, it may be that this festival will be significant for the informal conference that accompanied the plays. Director Tony Reekie’s programme of masterclasses and discussions for practitioners and promoters can only fuel the acceleration of quality being enjoyed in children’s theatre.