Why is the LDP so popular in Japan?
 

I understand Japanese is an overall Conservative culture and the LDP caters to their needs, but shouldn't there at least be an alternative party that could attain power in Japan (similar to the Republicans and Democrats in the US and the Liberals and Conservatives here in Canada)?

I know that left-wing coalition took power in Japan in 1993, but they were only in power for 2 years before the LDP won power back.