Taipei's registration window for this year's local elections is filling up fast, but the sitting mayor has not signed up yet — an unusual gap that leaves his party's top race in limbo.

• 80 city council candidates have registered in Taipei so far, including 42 sitting members seeking another term.
• Four people have registered for mayor, but Chiang Wan-an, the current mayor, is not among them.
• The declared mayoral field so far comes from the DPP and a set of small parties, not the KMT.
• Actress Liu Chih-yu registered as an independent for the Shilin-Beitou council seat, joining a crowded district that already has four sitting members running again.
• Registration closes September 4, so the remaining names have to come in within a day.

Outlook: Chiang is widely expected to file before the deadline, and the full slate for the year-end elections will be locked in once the window shuts.