I'm just back from Wigmore Hall, where I watched the Kopelman Quartet demonstrate chamber music playing at its best: exquisite refinement, complete togetherness, impeccable attention to detail. All with their lustrous sound and a whole lot of humour, although possibly a wee bit comfortable. And watching the Russian bow hold in action is a whole violin lesson in itself. It's interesting to me that Russian players rarely use the palette one associates with Russian music - the P