It's generally regarded that Hong Kong has the best subway in the world. There are many reasons for this, but one cannot be overstated: Hong Kong's geography. A huge portion of the city consists of long thin urban corridors sandwiched between mountains and the sea. As a result, Hong Kong need concentrate its funding on only a few subway lines to support a huge portion of the population. This good article aside, I won…
Side note, there actually isn't one shinkansen from Kagoshima to Hakodate, that route would take you on 5 different shinkansen lines: Kyushu, Sanyo, Tokaido, Tohoku, and Hokkaido. But I get your point.