It can be argued that whatever happens in Japan is what happens worldwide. Every game system that has dominated Japan in marketshare has also dominated worldwide marketshare.

Below is a listing of hardware sales through the first 21 weeks of a system. Along with thier lifetime sales and total weeks. Systems in red are generational leaders.

....System.......21wk Sales....Lifetime.......
Gameboy Advance - 3,222,219 (318wks w/ 16,678,823)
Playstation 2    - 2,685,290 (373wks w/ 21,847,292)
Wii         - 2,244,020 (21 wks)
DS        - 2,102,639 (125wks w/ 16,444,104)
Super Nintendo    - 1,402,928 (485wks w/ 16,701,578)
Playstation Port- 1,311,751 (124wks w/ 5,447,385)
Nintendo 64    - 1,282,854 (302wks w/ 5,377,174)
GameCube    - 1,185,178 (293wks w/ 4,019,836)
PocketStation    - 1,020,036 (168 w/ 4,545,076)
playstation 3    -   846,221 (24wks w/ 885,475)
Gameboy        -   733,602 (796wks w/ 31,301,470)
Dreamcast     -   709,548 (180wks w/ 2,232,028)
Saturn        -   693,404 (233wks w/ 5,718,528)
Playstation    -   668,677 (579wks w/ 19,362,986)
xbox        -   238,956 (195wks w/ 477,809)
Xbox 360    -   129,030 (72wks w/ 376,500)
Neo Geo Pocket    -    84,244 (143wks w/ 366,508)

As you can see the top 4 (ignore Wii) systems all went on to dominate sales in
both Japan as well as worldwide. The only generational leaders not at the top
are the Playstation and Gameboy.

What do these two have in common? They were both new market devices from their
repsective creators. Once they proved themselves they quickly dominated in sales.

Then their successors quickly took the lead by the 21 weeks and kept it, excluding
the Nintendo64, ofcourse that eventually lost out to the newcomer, Playstation.

So as for this generation. Wii is clearly on the path of a succesor device that will dominate Japan and thus, the world. 

xept genesis, sucked ass in japan but rest of the world loved it.

 except that snes outsold it worldwide still...........

@Hus:  Genesis only outsold the SNES in Europe which was a far more fractured and undeveloped video game market back then. 

Winning early in Japan is still important though not as much as it was from 1985-1995 when it could decide a console race almost alone.  Even so many major game developers are in Japan and they tend to favor the system that wins their home market.  It is possible to totally lose in Japan as the Genesis and Xbox largely did and survive but neither were terribly successful worldwide. 

If nothing else Japan is market that supports about 5 million console sales a year, doesn't help to lose them.  Sony and MS fanboys can come up with whatever excuses or hopes they want, but this is just another example that according to what we've seen so far and historical experience the Wii is heavily favored to win this console race by a large margin.

As much as Japan might determine the market leader, they never have determined by how much....That's a critical part of the issue.

Nintendo might rule with the Wii, but will it be 6:1 vs. the PS3, or 20:1 to the 360 as it is now? Heck no! It's statistically impossible aside from the possibility the PS3 sells 20m units and the Wii sells 120m units w/w.

Japan determines who wins in Japan, and since Japan is about 1/3rd of the global market (or maybe 1/4th now), it's obvious that who wins there ends up seizing the 2nd largest market in the world. It's very simple. If a company wins Japan, they get more J-dev support, and get a better launching pad for the rest of the world, which snowballs.

MS never had great support in Japan, yet it beat GC worldwide. Again, IMO, the Wii is Japans biggest market, and it's going to show....Incredibly...By the end of the generation.

 Genesis didn't sell in Japan (while it sold in the entire rest of the world outside of Japan) because Sega was originally an American company. This is well known in the history of videogames.

They carry that much nationalism. Just like how they treat Xbox..

Its that way the Saturn and PS1 were neck and neck until FFVII's release? Is that why Sega had and still does rule the arcade market? You are absolutely right, Japanese gamers sure do despise Sega because of its American roots.

yep first 21 weeks don't matter at all One must have game could change everything.

Also Japanesee will not dictate the sucsess a Microsoft machine. Japannese do not buy American systems for one reason or another. This alone almost annoys me enough to buy a 360 just because I am American.

well the one thing this chart should do is sent a clear message that the PS3 is not doomed. The original PS1 sold less in the 1st 21 weks than the PS3.

I don't think this arguement is  very useful as the worldwide leader typically thrives in all countries. All the systems like the ps2 that dominited in Japan also dominated the US and EUrope. It's hard to be the leader and not lead every major territory. And the US doesn't always follow down Japan's path look at X360 sales. This system isn't doing bad but by Japan's figures it should have sold less units then the ps3.

WOW Japannese people love NINTENDO for the 1st 21 weeks at least.....like 25% of all the gamecubes and N64's sold in Japan sold in the first 21 weeks...is that good for the Wii? the N64 had almost 2x the number of users in the 1st 21 weeks as the PS1 (sound familiar) The one thing Trend i see is in the console market Nintendo really shoots themself in the foot some how. If they could maintain sales they could have won every generation, but for some reason they can not, at least not with another Japanesee competitor. the super nintendo did well I think thats due to some misteps from Sega with the end of the Genisis' life . The SNES had a few misteps too...enter the Playstation