The mouth, or Chulnapgwan (Gate of Expression), determines communication styles, emotional expressiveness, and later-life food comfort (Sikbok). An ideal mouth is tight when closed but opens wide, with sharp lip borders and upturned corners (like a drawn bow, Yanggunggu). This signals optimistic warmth, drawing in helpful juniors and steady wealth. Downturned corners (like an overturned boat, Bokseonggu) result from chronic complaints, warning of lonely later years. AI filters measure corner elevation and lip symmetry, reinforcing that mindful smiling and encouraging language can physically elevate the lips and lift your fortunes.