[NTG-context] How do I typeset two close vertical lines as in ||x||=1 ?

I'm still having problems migrating from latex to context: In latex, I used to write e.g. $\| x \| = 1$, and get two vertical lines on each side of the x. In ConTeXt, the same "\|" is only producing one single vertical line. I tried using "||" and "\parallel", but in both cases the spacing is not as desired. Does anybody know how this is done properly? Thanks, Julian