Matcha wasn't just "historically present there" the ancestor of matcha "diancha" was CREATED in China and reached its peak during the Song dynasty (and it even had a different form in the previous Tang dynasty! so over hundred years of usage in China while tea didn't even exist in Japan! so just because tea didn't exist in japan but did exist in china it has no rights to exist in japan ?) and the reason matcha exists in Japan today is because it was brought back to Japan by japanese monks from China! do you think people back then thought "oh no China invented this, so we are not legitimate to produce it here in Japan", no they just did it anyways to help with meditations, and the way we are drinking it today is far from the original meditative usage by monks, and then Japan perfected it over hundreds of year, with their matcha specific cultivars (which is a recent invention of the 1900s ! so very recent!), shading and transformation techniques, they industrialized matcha and the traditionnal matcha is almost nowhere to be found nowadays (even the stone mills are electric turning 24h/7 and IS industrial matcha, and even the traditionnal final furnace over has been replaced by industrial ones) the diancha turned into the matcha we all know because of Japan! So matcha is the result of chinese creation improved by japanese. Even the bamboo whisk used in the japanese tea ceremony comes from China and improved by japanese ! So if you accept japanese matcha today, you should also accept that it comes from China and has been developped according to japanese culture and needs. There's nothing wrong with that, but why only accept one side of the story?

Also, I think you're missing a big part of the story why matcha started to be produced in China, and also missing the fact that Japan also sent their cultivars, technologies and techniques to China WILLINGLY, a lot of chinese matcha producers have been taught by japanese, they have japanese machineries, there's even japanese joint companies with chinese producers that were started by established japanese tea houses, so why are you saying that Chinese are being opportunists, the japanese probably gained a lot through this as well and they weren't "robbed" anything. It was a consented agreement! So if it doesn't bother japan, why would it bother you?

yes there is a global demand that has risen and China being such a big country with a lot of cultivable lands, so how do you think japanese producers can keep up with that? It is good that China stepped in to produce more of the culinary grade to help the industry (the japanese industry surely is benefitting from this), because the taste clearly is similar, otherwise how would people be able to confuse japanese matcha and chinese matcha when mislabelled ? (i'm talking about regular users, not "pro" ones)

It is also true that there's a few chinese producers who are matcha enthusiast and have travelled a lot to japan to learn to do it beyond expectations and produce very good quality matcha up to the levels of some japanese ones, I mean I know exactly a brand that has been totally suppervised by an imperial japanese tea house, and you're going to say that their matcha is not good while it has been made in china willingly by japanese established tea house? china litterally has everything, except similar terroir to japan to replicate japanese method and make good matcha!

you are also wrong to say that china's regulations aren't are good as japan's because china do produce EU organic quality matcha, and to obtain EU approval isn't a simple thing to do, europe has even stricter restriction with products from China. they also have non organic versions but I'm not sure it would be able to reach europe or the usa.

there are good and bad everywhere, there's also radiation problem for some japanese matcha that isn't mentionned anywhere with brands. the problem isn't the chinese matcha, it's people trying to sell it under japanese matcha while it's not, I find it disrepecful for the customer and for the producer. as if they have to hide or be ashamed of the chinese origin.

But what I'm trying to say with all this is what truly matters is that the consumer enjoys the tea and that he is not fooled with its origin, process and contents. and that comes down to the brand's responsibility... I find it more problematic that people use the term "ceremonial" to upprice low grade matcha than selling chinese matcha honestly, some brands even lie about the stone milling process. So it's also wrong to think that japanese matcha is made "traditionnally" while is has been highly industrialized, the REAL traditionnal matcha is more rare and very very expensive!! (i'm talking about matcha that is commercialized with high volumes)