Tetsuko Kuroyanagi has been one of Japan’s best-known entertainers for seven decades. At 90, she’s still going strong. As one of Japan’s best-known entertainers for seven decades, Ms. Kuroyanagi has interviewed guests on her talk show, “Tetsuko’s Room,” since 1976, earning a Guinness World Record last fall for most episodes hosted by the same presenter. Generations of Japanese celebrities across film, television, music, theater and sports have visited Ms. Kuroyanagi’s couch, along with American stars like Meryl Streep and Lady Gaga; Prince Philip of England; and Mikhail Gorbachev, the former leader of the Soviet Union. Ms. Kuroyanagi said Gorbachev remains one of her all-time favorite guests.