Why was Keyakizaka46's name changed from the original Toriizaka46?

When auditions were announced last year for Nogizaka46's sister group, the new group was to be called Toriizaka46.

It was only when the chosen members were introduced that it was revealed that the name had been changed to Keyakizaka46.

Why did they change it? And what do the names mean?

Keyakizaka Street

Both Toriizaka and Keyakizaka are streets in the Roppongi area of Tokyo. The "-zaka" part of both means "slope," just as it does in "Nogizaka," which is the name of a street outside the Roppongi area, but not that far away.

"Torii" refers to the torii gates to Shinto shrines. "Keyaki" is a kind of nicely-shaped medium-sized elm tree (zelkova serrata) that grows well in cities, provides shade, and has leaves that change colour in the fall.

Keyakizaka is one of the most high-class shopping streets in Tokyo, and with some of its most expensive land. It runs beside the high-class Roppongi Hills shopping centre and sports such shops as Louis Vuitton, Salvatore Ferragamo, Armani, and an almost-all-night Starbucks in the lobby of a big Tsutaya. There are also expensive apartment towers there.

The author of the article I've taken much of this info from says the street might as well be called "Bourgeois-zaka." Keyakizaka is also famous for its Christmas lights, both in the stores and in the trees along parts of it.

Toriizaka is a long, steep street with a variety of uses along it. Nice, but not as high class.

Several explanations for the change in names have been suggested.

1. There might be some kind of copyright or other claim on the name Toriizaka. In the past, there were residences for aristocrats and/or members of the Imperial Family there. This might lead to problems in the future. There's no indication this is the reason, but Sakamichi-group management has never given its reasons.

2. TV Asahi has its main office on Keyakizaka. Perhaps there were plans to do things with that TV network. But the Keyakitte, Kakenai? TV show, and the drama due to start in July are both running on TV Tokyo

TV Asahi

3. Early activities of the group were at the Zepp Blue Theatre, which is near (but not on) Toriizaka. Later activities have been elsewhere, particularly at the larger-scale Zepp Divercity at Odaiba. Maybe Aki-P once had an idea of setting up a Sakamichi group home-theatre at Zepp Blue, but changed his mind.

4. Last, and the probable real reason, is that management decided they wanted a high-class name, rather than one with the various associations of Toriizaka. "Keyaki" can be written in kana, as the street name is, or with a Chinese character that is quite complex and that not everyone knows how to write. The TV show even makes reference to this high-class complexity in its name, which means: "Can't you write keyaki?"

I myself have wondered whether the Keyaki-chans "dormitory" might be on Toriizaka, and they wanted to steer people away from there. All I know about their building is something Suzumoto Miyu said: that she could see the lights of Tokyo, and the Tokyo Tower in particular, from her room.

Anyway, no conclusion about the reason for the name-change until Aki-P or "Konno-san" (the chairman of the Sakamichi group management committee) tells us the reason. And that seems unlikely, lol.

Just to round out the story, the "Nogi"  in Nogizaka refers to General Nogi, who helped modernize Japan's army in the 19th century and won Japan's first victory over a Western country (Russia). After the death of the Meiji Emperor in 1912, General Nogi and his wife committed suicide together at their home. A shrine was built there called the Nogi Shrine, and the street leading up the hill to it is called "Nogizaka." The headquarters of Sony Music Entertainment, the record company that Aki-P works with on the Sakamichi groups (he works with different record companies for the 48 groups), is located on that street. 

Here's a map. The green area in the middle is the Roppongi Hills shopping centre. The road across the bottom of the shopping centre is Keyakizaka Street. The north-south street starting at the bottom right of the map is Toriizaka. You can see Nogizaka Station at the top left of the map (Nogizaka Street itself is above that, off the map). To walk from Keyakizaka Street to Nogizaka Street would take 15-20 minutes.