Seki-City in Japan has a blade-making history that predates the founding of the United States by several hundred years. There are a lot of great knives produced there, and I believe the first American companies to import quality knives from there were probably Kershaw and Al Mar. I believe Al Mar helped introduce Sal to the Seki makers to manufacture his original designs.
I have seen and owned some Japanese-made knives that were poorly-made, but most of those are fairly old (1970s), no-name novelty-type knives (i.e., faux "switchblade"-shaped knives). But I've seen poor knives from almost every other nation known for making quality knives, too (Germany, Italy, England, Taiwan, and, yes, even the U.S.). Of course, any time there is mass-production, you can also get a lemon here and there, regardless of its origin or company.
I like a lot of the Japanese steels, particularly VG-10. A lot of people still think that if a knife is made outside of the U.S., especially from Asia, that alone makes it inferior. I can't speak for China-made knives, as I don't own any; but many of the Japanese makers produce some of the finest knives anywhere in the world.
Jim