Ikejime (活け締め) or ikijime (活き締め) is a method of killing fish that maintains the quality of its meat. The technique originated in Japan, but is now in widespread use. It involves the insertion of a spike quickly and directly into the hindbrain, usually located slightly behind and above the eye, thereby causing immediate brain death. After spiking the brain, a thin needle or piece of wire is inserted into the spinal column's neural canal to prevent any further muscle movement. When a fish is spiked correctly, the fins flare and it relaxes, immediately ceasing all motion. Destroying the brain and the spinal cord prevents any reflex action; such muscle movements would otherwise consume adenosine triphosphate (ATP) in the muscle, which would result in the production of lactic acid and ammonia, making the fish sour, soggy, and less tasteful. Further, ikejime causes the blood contained in the flesh of the fish to retract into the gut cavity, producing a better coloured and flavoured fillet, and prolonging shelf life. This method is considered to be the fastest and most humane method of killing fish. Ikejime-killed fish is sought after by restaurants as it also allows the fish to develop more umami when aged.