Tenandan

The Fukami no Shinseina Tenandan (深みの神聖なテナンダン, lit. "The Divine Resurgence of the Depths") more commonly known simply as Tenandan, is the most important Genian cultural rite. It recalls the monumental moment of Gensokyo's history where Tenno defeated the God of Ash, Desudasuto, in the caves beneath Mount Orientalis. It is a period of solemn remembrance of Gensokyo's dark history, as well as celebration of the divine powers of nature. In the increasingly secular world, Tenandan has been adapted into other cultural festivals marking the arrival of spring or the harvest, for example the festival of Psantis Valoris in Tritonia.

Tenandan is a ten day long period in the Genian calendar, with the beginning day observing the Yogan no shunsetsu, (lit. "The Dredging of Lava"), where Mount Orientalis was believed to have erupted catastrophically, destroying all life and burying the land in thick ash. This day is also known as the Misute rareta hi (見捨てられた日, lit. "Day of the Forsaken") recalling how Wisteria abandoned Tenno as the cataclysm occurred. The most important day of Tenandan is the sixth day, which is the festivals namesake, "The Divine Resurgence of the Depths." It is said that, heading to Mount Orientalis, Tenno's presence was sensed by Desudasuto, and the volcano erupted again. Reaching the top, Tenno encountered Desudasuto, and the two engaged in a legendary duel floating above the lava. Ultimately, Tenno overpowered Desudasuto, and absorbed her powers. Renewed and strengthed, Tenno went on to revive the landscape and make it more bountiful than ever at the end of the sixth day. Days seven till ten commemorate this rejuvenation with feasts, gatherings and parties.

Notably, the most important part of the Tenandan festival is the Ningyō no Kami to Warutsu (人形の神とワルツ, lit. "The Waltz with the Puppet God".) Traditionally, as Tenno still contained Desudasuto's power, this rite would be performed at the location of the duel to quell Desudasuto's desires. Tenno would renounce Desudasuto's powers into a marionette, and the two would re-enact their legendary duel. This duel, which would normally amass hundreds, if not thousands of onlookers beside Tenno's high priests and priestesses, at its conclusion would mark the end of the solemn period, marked by fasting, and the beginning of the celebrations. Nowadays, due to the end of the Elemental Resurgence and the "renunciation" of Tenno's powers, the Ningyo no Kami to Warutsu is purely symbolic, and is not a necessary rite as Desudasuto's powers are assumed to have disappeared along with Tenno's.

Tenandan's occurrences are predictable, but not immediately so, requiring a deep knowledge of the ecliptic calendar. Following the rules, Tenandan will always begin (with the day of the Yogan no shunsetsu) on the first total solar eclipse to occur after the 1st Flarium (1st April). This total eclipse can occur at any time at any place on Yata, as the Theian Cataclysm led Theia to orbit the Sun at a distance further from Yata, as well as Doluro's perceived inconsistency in it's orbit since the cataclysm. The average time for any two solar eclipses to occur (regardless of location) on Yata is about 18 months. After two years, if no totality event has occured, the Yogan no Shunsetsu occurs on that 1st April, otherwise Yogan no Shunsetsu will occur on the day of the total solar eclipse. As such, there has been instances where periods of Tenandan have been separated by a short period of time, as a total eclipse had occurred just before the reset point of 1st April. The record shortest time is about three months due to the rarity of such events, whereas the predicted shortest possible times between Tenandan periods is 29 days, the length of the lunar month.