making one's stance clear; showing one's true colors
A yojijukugo used when someone clearly declares their position, allegiance, or intention, often in a political or organizational context. The literal image is of unfurling a banner to show one's side.
Before the election, each party made its stance clear.
He finally showed his true colors and joined the reformists.
A more general phrase for clarifying one's attitude, without the metaphorical banner imagery or the fixed four-character structure.
A similar expression using 旗色 (banner color), but less compact and not a yojijukugo.
A yojijukugo composed of 旗幟 (banner, flag) and 鮮明 (clear, vivid). The literal meaning is 'to unfurl one's banner clearly,' which metaphorically means to make one's position or allegiance unmistakably known.