Hi,Is there any good technique out there to understand a trading book risks ? i.e. trying to detect bad and/or obscure risks in a trading book ? In particular, in risk-management, one always runs all sorts of single-factor scenarios, like for instance FX spot ladder where only one currency is being bumped or down, and ditto on vols. But for instance, if your FX book (for instance) is mostly a spread position (e.g. spread between two currencies) then this kind of single-factor scenario wouldn't really capture this (it would large offsetting numbers). Sorry if my question sounds vague, but any direction would be welcome.Many thanks!

Try Litterman's Hot Spots and Hedges paper. You can fund more about that paper using the search function on this website.