Today's air combat is much more complicated than that of older times, as air-to-air missiles, radar, and automatic cannons capable of high rates of fire are used on nearly all modern fighter aircraft. New and additional types of manoeuvres have emerged, intending to break radar lock by minimizing the Doppler signature of one's own aircraft ("keeping the enemy at 3 or 9 o'clock"), or to exhaust the kinetic energy of an incoming missile (by changing the aircraft's course from side to side, the missile, not flying directly at target but trying to forestall it, will make sharper turns and will eventually have to fly a longer path). However, close-range fighting with infrared guided missiles and aircraft cannons still obeys the same general rules laid down in the skies over Europe in the early 20th century. The master rule is still the same: do not let your opponent get onto your six, while attempting to get on his.