If Sanseitō experiences a gain of seats in the 2026 Japanese House of Representatives election, then the market resolves to Yes. Seat changes are measured relative to seats held immediately before the election. Gains mean more seats than before; losses mean fewer seats. Only certified election results count. Seats not contested in the election are excluded from calculations. If a party is newly formed, all seats won count as gains. Changes in total chamber size don't affect the net seat calculation - it's based on absolute seat count changes, not proportional representation. This market will close and expire early when election results are certified.