The study explores the influence of domestic competition on international t
rade performance, using data from a broad sample of Japanese industries. Do
mestic rivalry is measured directly using market-share instability rather t
han employing structural variables such as seller concentration. We find ro
bust evidence that domestic rivalry has a positive and significant relation
ship with trade performance measured by world export share, particularly wh
en R&D intensity reveals opportunities for dynamic improvement and innovati
on. Conversely, trade protection reduces export performance. These findings
support the view that local competition-not monopoly, collusion, or a shel
tered home market-pressures dynamic improvement that leads to international
competitiveness.