A stage (面 Men) is a level in gameplay that contains obstacles, stage enemies, items, and the like. The player must pass a stage by defeating the boss at the end of each stage in order to proceed to the next stage or complete the game. Unlike other video games however, being a shoot 'em up, the Touhou Project contains the gameplay of danmaku, dodging bullets as the obstacles. The stages each have a unique theme and may also contain a midboss within the stage.
The player does not have the ability to freely travel around a stage to see its scenery, being a shoot 'em up. Instead, they wait for stage enemies and bosses to approach and shoot bullets at the player for them to dodge. Usually, when a player defeats a boss of a stage, the text "STAGE CLEAR" will appear. The background of the stages are in 3D and thus plays through a path of some sort as the stage proceeds. In the PC-98, as expected, they are in 2D. Also, each stage is located at a location of some sort, and they're also given an actual title.
Usually, each Touhou game as a total of 6 stages. Story of Eastern Wonderland had 5 stages, Highly Responsive to Prayers had 20 stages, and Fairy Wars had 3 stages. Despite being fighters with only bosses, the spin-off games are classed as stages.
On a game's title screen, There is a "Practice Start" that allows the player to select a certain stage if they've completed such stage on the main scenario, but this mostly exists on Windows games. There is also an "Extra Start" that has existed since Story of Eastern Wonderland that has an optional Extra Stage to challenge the player if certain conditions are met in the main scenario. Above this, there was a Phantasm Stage in Perfect Cherry Blossom.