Note: If "Shiina Ecchu" refers to a specific academic paper title or a different topic, please provide more context.

As Foreign Minister under Prime Minister Eisaku Sato, Shiina was instrumental in negotiating and signing the Treaty on Basic Relations between Japan and the Republic of Korea in 1965.

Before becoming Foreign Minister, Shiina played a decisive role in choosing the Prime Minister.

"Shiina Ecchu" is a title that encapsulates the fragile loyalties of Japan’s Sengoku period. The historical figure Shiina Yasutane, though a minor warlord, influenced the balance of power between the Uesugi and Oda clans in Hokuriku. His betrayal and fall illustrate the brutal necessity of realpolitik in 16th-century Japan. Today, he is remembered more for his epithet “Ecchu” than for any lasting achievement—a footnote in the shadow of Kenshin Uesugi and Nobunaga Oda.