Yoichi Masuzoe (TV personality, former Minister of Health), supported by the Liberal Democratic Party and Komei Party (ruling coalition in the national government): audience in 10s.
Morihiro Hosokawa (former prime minister), supported by former Prime Minister Junichi Koizumi (LDP), Democratic Party of Japan, Social Democrats: audience in 1,000s.
Toshio Tamogami (former Chief of Staff of the Self Defense Air Force), unofficially supported by Shintaro Ishihara: audience in 100s.
Kenji Utsunomiya (attorney - labor law) supported by Japanese Communist Party: audience in 100s - 1000s.
You would think Hosokawa is leading the race, and you would be dead wrong, if so-called opinion polls by the Japanese media are to be believed.
Here's one from anti-nuclear Tokyo Shinbun:
The Japanese media has already selected Masuzoe as the winner for reasons only known to themselves, no matter how seemingly unpopular he is with Tokyo residents.
Prime Minister Abe and Komei Party President Yamaguchi are going to join Masuzoe on Sunday February 2nd and give speeches in support of Masuzoe. The ostensible reason is to keep Masuzoe and his staff alert, not counting on the "huge lead" he already has. Sponichi (one of the tabloids) reports the likely venue will be the middle of Ginza in Tokyo, where both Masuzoe and Hosokawa with Koizumi are scheduled to speak.