Nicer viewing: L for Lightbox, F11 for fullscreen.
Shot with one hand-held speedlight in a Traveller8 mini softbox, untethered via YN-602.
I combined the exposures later-on in Phototshop, layer mode: Lighten.
Little trick besides the exposure fusion: With this type of strobe shooting, you can filter and adjust your lightsource later-on -- just by adjusting the layer opacity and by adding a Photoshop photo filter. As you can see, I trimmed left "light source" towards a warmer tone and the other one towards a cooler tone.
Well ... not the best aperture for that lens, but an aperture, that renders the whole knife sharp. Alternatively I could have stacked some shots -- which is not really easily possible with the chosen multi-flash exposure grick -- or I could have chosen a wider distance (which collided with the angle I chose).