The HZ Fishing Jar can be fired up or down multiple times simply by pushing or pulling on the immobilized tool string. A very low re-cocking force makes this design ideal for horizontal wells where pushing capabilities are limited. The jarring impact can easily be controlled by varying the applied force. No pre-setting or adjustments are needed before tripping in the hole or prior to jarring. A large thru bore is incorporated allowing ball actuated tools to be run below the jar.