The former site of Edo Castle and now the residence of the Emperor of Japan, the palace is mostly out of sight behind a moat, high walls and trees. The East Garden is lovely, and the circuit around the moat is popular with joggers. The public is only allowed across the impressive Nijubashi Bridge and inside the main gates on two days of the year: the emperor's birthday (23 December) and 2 January. There are free guided tours of the Imperial grounds Monday-Friday, which require advance reservations (either by phone or at http://sankan.kunaicho.go.jp). The East Garden, which contains remnants of Edo Castle and a traditional Japanese garden, is open Tuesday-Thursday, Saturday and Sunday 9 am-5 pm in summer; to 4:30 pm spring and autumn; and 4 pm in winter (entry allowed until 30 minutes before closing). Free. 1-1 Kokyo Gaien (near Nijubashimae or Otemachi stations on the Chiyoda Line), Chiyoda-ku, Tokyo. Phone 3213-1111.