and D$p'$ branes whenever $p + p' = 8.$, see e.g. [@Im; @CGS] for a worldvolume description of the D3/D5 case. At stage (i) when the NS5-brane is far from the D6-brane, the center of the NS5-brane subtends a small angle at the D6-brane and captures only a small amount of flux from the D6. As a result, essentially no D4 charge is induced in the region shown and one has only a flat NS5-brane. Then, as the NS5-brane approaches the D6-brane (ii), it subtends a larger angle and begins to capture some flux, generating some D4 charge. This charge corresponds to D4-branes lying inside the NS5-brane and running outward along this brane to infinity.

![Figure 1. Four stages of the Hanany-Witten process](stages)

When the NS5-brane is dragged past the D6-brane (iii), all of the flux from the D6-brane is captured in the part of the NS5-brane close to the D6-brane. Capturing one quantum of flux corresponds to the creation of one quantum of fundamental string charge, so that the thin neck of NS5-brane approximates a single D4-brane. However, the NS5-brane captures flux of the opposite sign in the region where the neck joins the asymptotically flat part of the 