oneworld Multi-Carrier Awards Wiki v0.1

Rules
1. You need two non CX/KA carriers
2. You are allowed 5 stopovers, 2 transits (<=24hrs) and 2 open jaws. You can use your stopover allowance as a transit, possibly by asking for it to be ticketed as such (extra taxes?). [Using stopover for transit is no longer possible since 2021/22?]
3. The open-jaw points do not count towards your stopover allowance. Neither does the final city on the itinerary
4. You must start and end in the same country.
5. To determine the miles required, add up all flight sectors on your itinerary and look up the award chart (ignore the distance between open-jaw points). gcmap.com is handy, though best to go via asiamiles' calculator.
6. Co-terminals (NRT/HND, LHR/LCY) do not count as an open-jaw (takes up 1 stopover/transit allowance).

If an itinerary clears the above, it is valid, though you may have to argue a lot back and forth. Keep your patience suit on and and keep referring to the terms & conditions ("What in the T&Cs makes this invalid" tends to work).

For the examples below, x=transit, o=stopover, and capitalized alphabets represent airports.

Some valid routings that have commonly been pushed back on
1. "You cannot go through the start, destination, or enroute point more than once". A-oB-oA-oC-oD-A is a valid itinerary.
2. "An open-jaw point is a stopover". A-oB-oC-D//E-oF-G//H-oI-oJ-A is valid, as is A-oB-xC-D//E-oF-G//H-xI-oJ-oK-oL-A.


Other tips
1. Tickets are valid for 1 year from the date of issuance. Potentially a pain when planning that dream RTW trip involving LATAM/AA which release seats 330 days out, that you're trying to tee-in with CX award seats released a year out.
2. A combination of BA/AA/LATAM/QF sites works well to research availability (look for saver availability)
3. You can go crazy on the routings- A-oB-A//C-oD-C//E-A is fine if A,B,E are in country/Region # 1, and, C,D are at the other end of the world.