A historical news fact. 昭和天皇 ('Emperor Shōwa,' Hirohito, reigned 1926–1989). 参拝 is the standard term for visiting a shrine or temple in worship. 靖国神社 (Yasukuni Shrine) controversially enshrines Japanese war dead including Class-A war criminals (enshrined in 1978), which is why the Emperor stopped visiting in 1975 — a politically sensitive point in Japanese history. ~までに ('by X') marks a deadline/endpoint.