This simple run -rig allows the fish to run freely with the minimal of resistance. The rubber bead protects the mainline knot from the swivel. This set up is prone to tangles during a long distance cast.
Added by Julian Grattidge;
I’ve found the best use of this rig is when targeting shy feeding fish. The aim of the rig is that when the bait is picked up, the fish can move off from the spot without moving the lead, and thus often does not realise it has been hooked as there is no resistance from the weight of the lead. However, as the fish will obviously be taking line through the running ring, it will quickly register on your bite indicator, often allowing you to strike before the fish even knows it has been hooked.
I have found the rig to be extremely effective when fishing at distance where there is a danger of a fish picking up a fixed rig and kiting left or right without registering a take. As Gaffer has mentioned, if set up as per the picture above, you can have problems when distance casting, but many manufactures now sell purpose built running rig components which eliminate any difficulties.
We have used this method to great effect on Birch Grove, where you are targeting shy feeding fish near to snags, and thus indication needs to be spot on.