the star-perfomer and prized magnolia of Japan has to be the Star Magnolia or Magnolia stellata.
Quiz: Why is the plant called the Star Magnolia?
Answer: Because of the flowers that form a star shape by its petals.
The Star Magnolia which have been grown in Japan for hundreds of years as flowering pot plants called “Shidekobushi” and can be seen in the World Heritage beech forests of Shirakami and elsewhere.
For photos of the tree and flower, see this page.