Ko-ro Tower (Drum Tower) (鼓楼)
From ancient times, drum towers (ko-ro towers) were built inside castles, cities and the sites of religious institutions in the People's Republic of China and areas influenced by the Chinese culture. The drum tower is a multi-storied building designed to inform people of the time or to give signals. Normally a drum is set inside the tower. Drum towers are also called taiko-ro in Japanese. A sho-ro tower (bell tower) is similar to a ko-ro tower.
Bell towers (sho-ro towers) were also designed to give time signals and many of them were built in pairs in Chinese provincial capitals. A bell tower was normally built in the east and a drum tower in the west. The bell was rung early in the morning and the drum was beaten in the evening; this was referred to as 'shinsho boko' (morning bell and evening drum). As can be seen in the bell and drum towers in Beijing (Beijing Gulou and Zhonglou), some have a bell tower in the north and a drum tower in the south while others have bell and drum towers in a single building like in Shanhaiguan shodrum tower.
The Drum Tower in Nanjing Castle
The Drum Tower in Nanjing Castle is located in the center of Gulou district, Nanjing City. It was built in 1382 during the Ming Dynasty and used for signalling the times of day and night and for welcoming kings.
Now the area is a park, and the Drum Tower (Gulou) Park and the site adjacent to the park is Drum Tower Square; a public square. The park is open from 8 a.m. to 5:30 p.m. (as of 2004) and is free to enter, but a fee (five yuan as of 2004) is charged to climb the drum tower. There is a stone monument, a bell and a drum on the second floor of the Drum Tower. You can ring the bell and beat the drum for an additional fee. Old photographs of the Drum Tower are displayed on the third floor, which recall Nanjing in the past. The closest subway station is Drum Tower and Agricultural Bank Station on Nanjing Subway Line 1.
Also in Japan, drum towers referred to as taiko-ro tower can be seen inside religious institutions such as temples and shrines. In some cases taiko-ro towers and bell towers are built together and in other cases built by themselves.
The buildings are multi-storied, and in order for the sound to go outwards their openings are wide or sometimes they have an open structure with only columns and rails.
Taiko Yagura in Castles
The taiko yagura was a building which had the same role as a drum tower in a temple and which normally announced the time of gate openings at sunrise and sunset. All castles had a taiko yagura, and a kane yagura (bell tower) was similar to the taiko yagura.
Many taiko yagura are multi-storied, and a one-storey turret such as the one in Himeji-jo Castle is rare. The first storey was made in the same way as a normal turret and the second storey had large windows and a hanging drum. Taiko yagura are sometimes made decoratively; using kato-mado windows (pointed arch or bell-shaped windows) or surrounded with parapets.
Examples of existing taiko yagura include those in Himeji-jo Castle (one-storey turret) and Kakegawa-jo Castle as well as in Hiroshima-jo Castle, which was restored.