Dear! Thunderbolt Fire refers to Naiyin Ming. Generally, the horoscope in the four pillars and horoscopes refers to the heavenly stem of the sun. Whether Kai and Yu can be used depends on the horoscope's xiyongshen. If the zodiac is not fire, use fire but not water. For wood, wood cannot use metal. It may sound laborious. How do you want to get a good knife? Metal must be forged with fire to make a weapon. Kai: Triumph. Yu: Time is vast. The meaning is very good, why can't it be used? Don't stick to folk customs and taboos, one is fate, two is luck and three is feng shui. Water sharing is ranked third, and the name can be ignored. As long as the meaning is profound and easy to remember, it will be fine. Hope this helps you...