The Timeless Dojo is a special residential building that is only obtainable by collecting fragments of the Timeless Dojo Selection Kit, given as a time reward for finishing a Feudal Japan Settlement within a certain amount of time.
The Timeless Dojo Selection Kit provides a choice between a new level 1 Timeless Dojo building or a Timeless Dojo Upgrade Kit.
The Timeless Dojo produces coins. When it is motivated, its coins production is doubled and all special productions are enabled. The production is also affected by the town's happiness and by boosts of certain Great Buildings and it gains additional boosts after being upgraded. The building can be plundered if it isn't motivated. On the highest Level, the Timeless Dojo produces a random Military Unit of the buildings age.
The Timeless Dojo can be upgraded with a Timeless Dojo Upgrade Kit item. To upgrade the Timeless Dojo, use the Timeless Dojo Upgrade item on the Timeless Dojo that is already situated in your city. Its upgraded version will then be placed directly on the same spot in your city and the production timer will not be reset. Note that the upgraded building will be from your current era, even if the old one was from one of the earlier ages.