I've asked about the different kinds of powdered tea used on specialised tea forums, I don't understand at what point konacha becomes matcha and there seems to be a wide rainbow between them.

It's not an answer I've been able to find in English, and none of the self described tea connoisseurs new anything about (or had much interest in) the topic.

My take is that KitKat use some kind of powdered green tea to flavour their main products but whatever that tea is, it is not the matcha I know and love, and, considering what it takes to grow and harvest matcha, I am not even a tiny bit surprised about that. I'm sure this is true for the vast majority of commercial scale products labelled as matcha flavour in Japan.

Ito Kyuuemon ltd edition is a tie in with Itoh Kyuemon - a confectionary company who specialise in green tea flavoured products: http://www.itohkyuemon.co.jp. I'd never heard of them before and now I have, thanks to the KitKat tie in, more specifically I know who they are now because they are at least partly responsible for matcha kit kats having a better taste than usual. How these tie ins work, if Itoh Kyuemon are partly subsidising the increased cost of the higher grade powdered tea, if they supply it themselves, etc... I truly have no idea.

In short, I do not know what it is that is being used in mainstream confectionary and labelled as matcha. If anyone knows anything about the vast array of tea powders that inhabit the spectrum between sushi shop konacha and tea ceremony matcha I'd love to find out more.

P.S. Couldn't bring myself to write 抹茶 as maccha - too much like an offering from a certain burger chain.