Obon, also known as Ulambana, is a three day Shinto Buddhist festival to honour the spirits of our ancestors and loved ones. This Buddhist-Confucian custom has evolved into a family reunion holiday when people return to their ancestral home and visit their ancestors' graves. It is also believed that on this day the spirits of ancestors revisit the household altars.
The three days of Obon are 13th to the 15th day of the 7th month of the year. If using a solar calendar this equates to July. However, according to the lunar calendar the 7th month co-insides with August. Obon is usually observed in mid August but I have seen some references to it being in September as well.
This tradition stated over 500 years ago and traditionally includes a dance, known as Bon-Odori. Although it is not an official public holiday in Japan most people do have a at least one day off. It is celebrated through the lighting of bonfires, sacred meals, paper lanterns and dancing.
Obon,” from Sanskrit’s “Ullambana,” suggests great suffering, as the full term translates into “hanging upside down.” Bon-Odori—and the Buddhist legend stems from the time of Gautama Buddha who he instructed his disciple Maudgalyayana on how to release his mother from suffering in the realm of the Hungary Ghosts by making offerings to Buddhist months on the 15th day of the seventh month ensuring his mother’s salvation.
Buddhists believe the gates of hell are opened during this month, and family members give offerings and prayers of thanks and appreciation of the worldly suffering they endured on their behalf. On the 14th day, a grand feast is organized for the ghosts and to ward off evil spirits. Nowadays some East Asian countries celebrate with live performances for the entire community. Interestingly the first few rows are left empty to seat the ghosts. Priests and monks perform rituals by throwing rice and other small foods into a fire which open the gates of heaven and liberate the spirits.
Further Information
A primary purpose of Obon is to ease the suffering of deceased loved ones while expressing joy for the sacrifices loved ones have made. Thank you https://www.readthespirit.com/religious-holidays-festivals/ullambana-and-obon-buddhists-japanese-celebrate-summer-festival/