Taipei's mayoral race is heating up, with a rough public exchange for incumbent Chiang Wan-an and stronger-than-expected polling for challenger Puma Shen — bad news for the KMT's hold on the capital.

• Chiang Wan-an came off badly in a public question-and-answer exchange, and the clip spread fast.
• Puma Shen, the DPP's likely standard-bearer in Taipei, is polling better than his party's usual base in the city.
• That reach beyond core DPP voters is the real story — Taipei has leaned KMT, so a challenger pulling in swing voters changes the math.
• Incumbency still favors Chiang, who has led most head-to-head numbers up to now.

Outlook: Expect both camps to lean harder on polling and viral clips as Taiwan's local elections draw closer.