"Hanchin-set" was a term used to describe the setting of gas giant Hanchin below the horizon of the moon Qina. The term was developed by the natives to the moon to describe the phenomena by which a portion of Qina's surface was not covered by light. One of these rare and brief occasions occurred at mid-winter. During this Hanchin-set, the Vashan were known to cough up sin-bullets.
The phenomena of a Hanchin-set caused darkness over a portion of the moon, because light radiated and reflected from the gas giant and bathed Qina in a measure of light for the majority of the year.