Yokkaichi (Japan) and Setagaya (Japan) are 285 km (177 mi) apart in a straight line. The way we suggest is by train and bus, via Nagoya, Shizuoka and Tokyo: about 3h 30m door to door with 3 changes, for ~€24–92 per person. No flight is needed.
Step by step
Train from Yokkaichi to Nagoya: about 35m, 35 km, ~€2–15
Train from Nagoya to Shizuoka: about 50m, 136 km, ~€9–40
Train from Shizuoka to Tokyo: about 1h, 142 km, ~€10–45
Bus from Tokyo to Setagaya: about 20m, 7 km, ~€1–2
Every route we know
Train + Bus, via Nagoya, Shizuoka and Tokyo: about 3h 30m, 3 changes, ~€24–92
Bus + Train + Bus, via Kyoto and Tokyo: about 4h 55m, 2 changes, ~€38–122
Train + Bus, via Osaka and Tokyo: about 4h 55m, 2 changes, ~€40–142
Questions
How long does it take to get from Yokkaichi to Setagaya?
About 3h 30m door to door by train and bus, via Nagoya, Shizuoka and Tokyo, including time for changes.
How much does it cost to travel from Yokkaichi to Setagaya?
~€24–92 per person for the route we suggest. These are estimates from travel-guide prices and published tariffs, not quotes: check the operator for today's fare.
Is there a direct train from Yokkaichi to Setagaya?
Not that we know of: the routes in our data change via Nagoya, Shizuoka and Tokyo.
Times are rough door-to-door times, with time to change included. We don't have timetables, and fares are rough estimates, not quotes: check Google Maps or the operator before you travel.