The tower's design was published on 24 November, 2006, based on the following three concepts:
Fusion of neofuturistic design and the traditional beauty of Japan
Catalyst for revitalization of the city
Contribution to disaster prevention – "Safety and Security"
Tokyo Skytree also resembles a 5-storey pagoda from historical Japan. The base of the tower has a structure similar to a tripod; from a height of about and above, the tower's structure is cylindrical to offer panoramic views of the river and the city. There are observatories at, with a capacity of up to 2,000 people, and, with a capacity of 900 people. The upper observatory features a spiral, glass-covered skywalk in which visitors ascend the last 5 meters to the highest point at the upper platform. A section of glass flooring gives visitors a direct downward view of the streets below.
Earthquake resistance
The tower has seismic proofing, including a central shaft made of reinforced concrete. The main internal pillar is attached to the outer tower structure for the first above ground. From there until the pillar is attached to the tower frame with oil dampers, which act as cushions during an earthquake. Additional resilience is achieved through an "added mass control mechanism" – a damping system which, in the event of an earthquake, moves out of step with the building's structure, to keep the center of gravity as central as possible to the tower's base. According to the designers, the dampers can absorb 50 percent of the energy from an earthquake.
Color
The exterior lattice is painted a colour officially called "Skytree White". This is an original colour based on a bluish-white traditional Japanese colour called.
Illumination
The illumination design was published on 16 October 2009. Two illumination patterns Iki sky blue and Miyabi purple will be used, alternating daily. The tower is illuminated using LEDs.
Naming and height
From October to November 2007, suggestions were collected from the general public for the name to be given to the tower. On 19 March 2008, a committee chose six final candidate names:,,,,,. The official name was decided in a nationwide vote, and was announced on 10 June 2008 as "Tokyo Skytree". The name received around 33,000 votes out of 110,000 cast, with the second most popular name being "Tokyo Edo Tower". The height of was selected to be easily remembered. The figures 6, 3, 4 stand for "Musashi", an old name of the region where the Tokyo Skytree stands.
Broadcasting use
Tokyo Skytree is used as a radio/television broadcast and communications tower.
Television broadcasters
Radio broadcasters
Timeline
2008
14 July 2008: A ceremony was held at the site to mark the start of construction.
2009
6 April 2009: The foundations for the three main legs were completed.
7 August 2009: The tower reached a height of 100 m.
16 October 2009: The projected height was increased from 610 m to 634 m to make it the highest self-supporting steel tower. Also, 6-3-4 is Mu-sa-shi in Japanese wordplaygoroawase.
10 November 2009: The tower reached a height of 200 m.
2010
16 February 2010: The tower reached a height of.
29 March 2010: The tower reached a height of, becoming the tallest structure in Japan.
30 July 2010: The tower topped 400 m, reaching a height of.
11 September 2010: The tower reached 461 m, becoming the tallest structure ever built in Japan, surpassing the dismantled Tsushima Omega tower of 455 m.
23 October 2010: The tower reached a height of, and assembly of the main tower section was completed.
20 November 2010: Two tuned mass dampers with a total weight of 100 tons were temporarily placed on the tower tip at 497 m.
1 December 2010: The tower topped the mark and reached a height of, beating Taipei 101. A lightning conductor and two tuned mass dampers were docked to the gain tower, which was gradually lifted within the central shaft.
18 December 2010: The transmittingantenna for digital terrestrial television began to be installed.
2011
1 March 2011: The tower topped the mark and reached a height of, surpassing Canton Tower and becoming the world's tallest tower.
12 March 2011: The tower reached a height of. A full inspection was made, looking for possible damage by the 2011 Tōhoku earthquake and its aftershocks.
18 March 2011: The tower reached its final height of at 1:34 pm JST.
23 May 2011: Dismantling four tower cranes continues till mid-July.
17 November 2011: Guinness World Records certified the Tokyo Skytree as the tallest free-standing tower.
2012
16 February 2012: The roofs of warehouses close to the tower were damaged by falling snow and ice from the tower.
29 February 2012: Tower construction was finished. Completion was delayed two months from the original schedule because of a shortage of supplies due to the effects of the 2011 Japanese earthquake and tsunami.
2 March 2012: A ceremony was held to celebrate the completion with a kannushi priest and 70 people from Tobu Group, construction, broadcasting and other companies.
6 March 2012: First Light-up during the Tokyo Hotaru Festival
1 October 2012: Channel 9 Tokyo MX start transmission from Tokyo Skytree with continuing transmission from Tokyo Tower in simulcast manner.
2013
16 January 2013: Snow falling from the tower knocked a hole in the roof of a nearby house. No one was reported injured.
13 May 2013: Tokyo MX continued transmission from Tokyo Skytree and stopped transmission from Tokyo Tower with a gradual decrease in power since 12 November 2012.
31 May 2013: On 9:00 a.m., formal transmission of broadcast in channel 1 to 8, except 3, start from Tokyo Skytree after number of test transmission with off for minutes to hours from Tokyo Tower since 22 December 2012.
Opening
As the Skytree's opening approached, people reportedly waited in line for a week to get tickets. By the opening, trips up the tower were fully booked for the first two months of operation. The opening day drew a crowd of tens of thousands, despite rainy conditions which blocked the view from the tower's observation deck. Strong winds also forced two elevators to be shut down, leaving some visitors briefly stranded on the observation deck. According to Tobu, 1.6 million people visited Skytree in its first week. Local residents reported that the influx of visitors disturbed the peace of their community and had, so far, generated little economic benefit for the local area.
