[NTG-context] how to start all chapters on a left page

Dear all, Does anyone know how to start a chapter on a left page in a doublesided paper? Every chapter consists of two pages which I always want to start at the left side. Whatever I try, \chapter always starts with a right page. Liesbeth van der Plas -- liesbethvanderplas@gmail.com www.wiskunde-interactief.nl