Imperial East Garden Palace

Can I visit the Imperial East Garden without any guided tour?

I visit the Imperial Household Agency Reservations website and the map shows that the guided tour is actually outside the East garden. So can I tour the east garden myself without any reservation?

Thanks.

Can I visit the Imperial East Garden without any guided tour?

Yes, you explore it freely on your own.

will I be able to explore this area on 31st Dec or 1 Jan?

By way of caution, Imperial Palace in Tokyo have 3 gardens.
Booking and entrance fee are unnecessary in every garden.
1. HigashiGyoEn the East Garden
It opened in the daytime only and closed occasionally.
http://www.kunaicho.go.jp/event/higashigyoen/gyoen-close.html
2. KitanomaruKouen the North Garden
Always opened.
3. GaiEn the Outside Garden
Always opened.
http://www.env.go.jp/garden/kokyogaien/english/index.html

will I be able to explore this area on 31st Dec or 1 Jan?

No, it is closed from December 28 through January 3.

http://www.japan-guide.com/e/e2276.html