Uso-gae is one of the Shinto rituals practiced on January 7th every year at Dazaifu Tenman-guu Shrine in Zaifu, Dazaifu City, Fukuoka Prefecture.
It is based on a homonymous word play of “鷽” (pronounced uso, meaning a bullfinch bird) and “嘘” (pronounced also uso, meaning a lie). Attendees to the ritual bring their own small wooden bullfinch.  They gather inside a sacred area of the shrine enclosed by straw festoons and exchange their wooden birds with each other saying “Let’s change, Let’s change”.
It is believed that, by doing so, people can cleanse themselves of all the lies they made unintentionally or circumstances forced them to make, and ask the deified spirit of Sugawara Michizane for forgiveness and to be given good fortune to start a new year.  
The exchanged wooden bullfinch is later enshrined in the household Shinto altar or a sacred alcove in the house to receive the year’s good fortune.
Uso-gae is a Shinto ritual similar to the concept of repenting in Christianity.