[NTG-context] starting on an even page

This is undoubtedly a simple-minded question. So, with apologies, let me say that I wish to produce a chapter in doublesided mode that begins on an even (left hand) page, say page 54. What I currently produce is a blank page 54 (with correct header) followed by the chapter itself starting on page 55 and looking exactly it should if page 55 were the first page. In effect, ConTeXt is inserting a blank page so that the first page of the chapter proper is odd. How do I stop it from doing this? (There is no blank page if the first page number is in fact odd.) Any suggestions or even pointers to some manual would be much appreciated. Alan