Could someone who lives in Japan tell me why they do not use street names or signs?

How would one navigate a large city? For instance, I was in 仙台 and I cannot imagine getting around without any street signs or street names at all.

Large cities usually have street signs that hang near the traffic signals. Residential areas often have billboards that list the names of people who live in the area and where they live.
When trying to find a new location. I go to google maps and trace my path from the nearest station.

zachandhobbes Wrote:How would one navigate a large city?

Landmarks, station names, maps.

Most large cities have street names.

It's just a different system of addressing. Though, yes, you do need a map with this one.

An example address might be 東京都大田区洗足池5の8の10

That would be in Tokyo, in Ota ku, in the Senzoku Ike neighborhood, 5th section, block number 8, the 10th location around the block. Once you get used to it, it's not that difficult. You'll often see maps from the nearest station in ads and the like, and if you're going to visit someone they will probably give you a sketch map to follow.

Neighborhood maps and often printed up, especially in rural areas, with ads for the sponsoring businesses all over the back of the map or around the edges.

The different parts of the address might have different names depending on where you are, city, or country, or where ever, but the basic principles remain the same,

Some Japanese roads intersect themselves, or take a really convoluted route, making street names either impossible or borderline useless.

Some cities have real street names which are useful for getting around. Kyoto is a good example.

There was a TED talks that addressed this. Check it out:
http://www.ted.com/talks/derek_sivers_we...erent.html

Awesome talk! really clears things up.