reception hall; guest house
A building or hall for receiving and entertaining guests, especially state dignitaries. Can refer to such facilities in general.
A new reception hall was built in the city center.
State Guest House
Specifically refers to the official State Guest Houses in Japan, most notably the Akasaka Palace in Tokyo and the Kyoto State Guest House.
The Akasaka Palace State Guest House is used to entertain state guests.
The Prime Minister held a welcome ceremony at the State Guest House.