Taiwan's Changhua County race for magistrate is shaping up as a four-way contest, but the real fight is over turnout and swing voters rather than party loyalists.

• The blue-green base vote in Changhua has stayed flat for years, so winners need swing voters and first-time voters to get over the line.
• The DPP's Chen Su-yueh is a vote magnet in the south of the county, but has to push north to win back the seat.
• The KMT's Wei Ping-cheng started late and is still dealing with fallout from the nomination fight, though he inherits eight years of incumbent record and party machinery.
• Two independents are the wildcard: former Changhua City mayor Chiu Chien-fu overlaps most with the DPP base and likely hurts Chen more than the KMT.

Outlook: Whichever side can mobilise its own supporters and pull in undecided voters takes the county, with the independents' vote share the deciding variable.