China-Japan relations in the wake of Japanese PM Sanae Takaichi’s remarks on Taiwan represent “the most dangerous situation in the past several decades," says a Taiwan-based journalist and political analyst.

China has expressed serious concern over Tokyo’s recent military threats, warning citizens to avoid travelling to Japan.

Japan's ruling party picked conservative nationalist Sanae Takaichi as its new head on Saturday, putting her on course to become the country's first female prime minister.