Lhabab Duchen
Lha Bab Düchen (Tib. ལྷ་བབས་དུས་ཆེན་, Wyl. lha babs dus chen) is one of the four major Buddhist festivals commemorating four events in the life of the Buddha, according to Tibetan traditions. Lha Bab Düchen occurs on the 22nd day of the ninth Tibetan lunar month and celebrates Buddha's return to the human realm after teaching his mother for three months in the Gods realm. It is widely celebrated in Tibet and Bhutan. The festival is also celebrated in other Buddhist Asian countries, including Sri Lanka, Myanmar, Thailand and Laos, where it is celebrated a few weeks earlier.
Lha Bab Duchen is a Buddhist festival (duchen) celebrated to observe the Buddha's return from the Gods realm, referred to as Indra's realm, as Tushita, as the Heaven of the Thirty-Three, and as Trāyastriṃśa heaven. His return to the human realm is considered one of The Eight Great Events in the Life of Buddha.
According to events in the Buddha's life, the Buddha ascended the Gods realm at the age of 41 in order to give teachings to his mother, who had been reborn in Indra's realm. He stayed for three months to repay her kindnesses, while also benefiting the gods in that realm.
He was exhorted by his disciple and representative Maudgalyayana to return, and after a long debate and under a full moon the Buddha agreed to return. He returned to the human realm a week later by a special triple ladder prepared by Viswakarma, the Hindu-Buddhist god of machines. 
On Lha Bab Duchen, the effects of positive or negative actions are multiplied ten million times. It is part of Tibetan Buddhist tradition to engage in virtuous activities and prayer on this day.
Abhidhamma Day
== Notes ==
During this day, positive or negative actions are multiplied 100 million times.
http://www.fpmtabc.org/prayers_mmdays.php
https://fpmt.org/media/resources/dharma-dates/ and select November
Buddhist Art News https://web.archive.org/web/20160304214148/https://buddhistartnews.wordpress.com/2013/12/04/lhabab-duchen-the-day-buddha-descended-from-tushita-heavens/
Legge, James, tran. A Record of Buddhistic Kingdoms. Oxford: Clarendon Press, 1886; reprint, New York: Dover Publications Inc.,1965. Chapter XVII.
== External links ==
Professing Faith: Story of the Tibetan Buddhist festival of Lhabab Duchen