Good matcha's savoury before it's sweet. Umami hits first, that same broth-y depth you'd get off seaweed, or a decent hard parmesan if you're after a stretch. Then the grassiness turns up, vegetal, a bit green. And underneath the whole thing, sweetness, just sitting there, lingering. All of it traces back to the shading; no other way round it. Honestly? That's the entire reason the practice stuck.
Bitter. Chalky. Fishy. None of those belongs anywhere near a good bowl. Bitterness, nine times out of ten, means the water ran too hot, or somebody reached for the wrong grade. Chalky's easier still: powder that never got sifted. And fishy, that hay-like note creeping in? Old matcha. Oxidised. Doesn't take long either; a few months after opening the tin and it's already turning. Once it's gone that way, there's no bringing it back. None.