Thank you for the quick reply: booked via TA; ticketing airline is QR; I did ask for codeshares.

My assumption is that the bulk of the charge is YQ / YR, but ultimately I'm curious to understand what would be determining factors for the entire amount. When I asked the TA (and it was to a certain extent moot because i was going to book the ticket anyway) I was told they couldn't know without some trial and error on different routes etc. I'm trying to find out more, so that when I book next time, I can go into the process with a more informed view as to what works and what doesn't. For example, I could just as easily do an ex-TYO DONE4 (which appears to have a good base ticket price, based on the latest table I've seen), and would do so if that made a material difference to the taxes and surcharges. There was a comment up thread about India introducing a premium for business class cabins, which was what prompted me to ask my original question - I presume that would not count as YQ / YR if I've paid it.

If I asked the TA, should they be able to give me a line by line breakdown of the taxes?