The ritual of karn bucha thian can be held any time of the year. The purpose is to boost people's morale and make them feel good. The person conducting the ritual is usually a monk or an elder who has been in monkhood. He will make two special candles, cite some incantations in reference to the person asking for the ritual, and light the candles. One candle is for getting rid of bad luck and the other is to promote longevity. The monk or elder performing the ritual then watches the flames. Bright and long-lasting flames mean good fortune. Flickering flames and crackling candles mean some bad fortune. If the flames are only twinkling or the lights go out, this means the person is facing very bad fortune or even death.

The ritual is held when a person is facing or likely to face a misfortune as it is believed, for example, when a person has been in a small accident, had a bad dream, turns 25, is involved in a court dispute, or is ill. In addition, it is held at the New Year Festival, anniversaries, when predictions of bad fortune have been made or Birthday.