Sorry. The answer may be obvious to some but I want to be sure. In a way this is a generic question but likely the tickets would be CX hence putting it here.

I know if you buy a ticket from A to C and if it needs to stopover in B, and if there is a delay in the leg A->B, the airline will get you to C eventually.

However, what happen if I deliberately break it up. Like, I buy (in one ticket) A to B, self-made a stopover of 10-14 hours, then B to C. What happen if there is a delay on the leg of A to B beyond 10-14 hours, would the airline still get me to C free of charge? Here is a solid example: Normally a flight from LHR to ICN would stopover HKG for a few hours but I want to break it up so that it is LHR->HKG, 10-14 hours later HKG->ICN. What if there is a delay on the first leg beyond 10-14 hours, would the airline still ship me to ICN on the next available flight?

Grateful for some clarification here please.

Someone familiar with CX's policy re: protecting across separate CX => CX tickets will, I'm sure, be along shortly to answer your question.

But I trust you realize that you can have a connection of up to 24 hours on an international ticket. Would booking a longer connection solve your problem?

Many thanks @guv1976 for the help in advance. Many thanks also for the great suggestion but I normally search flights on skyscanner, play around until I get the right combination. Skyscanner do not normally have very long stopover and it seems more complicated then if I have to find an agent, as I would lose the interactivity of playing around to find the right combination.

Furthermore, it is also a bit more complicated. The journey I described is for our daughter for her 'short' two-week holiday in HKG, but we want to put a 'seamless' trip to Seoul in the middle. So the plan is for her to buy LHR->HKG (then leave big suitcase in HKG), then HKG->ICN soon/the following day, we then have a 4-5 days trip in Seoul, then she completes the rest of her journey of ICN->HKG, stay for another 8-9 days then HKG->LHR. My wife and I would just buy a set of date-matching return ticket for HKG<->ICN. I hope this is clear. Not sure if I overthink the whole thing but I would like (1) no missed flight for her to ICN, and (2) the ability to leave a big suitcase in HKG while we go to Seoul.

Buy it as one ticket. If you scroll down when selecting flights, you usually get options with long stopovers. I do this all the time as I live in HK and often chose the ones with an overnight stop so I can go home for a sleep inbetween flights.

Thank you and this is a very good idea. I will look out for this option in the future.

However, in this particular case, it is slightly complicated. This is actually for our daughter who comes on a two-week holiday in Hong Kong. We want to take this opportunity to visit Seoul together. In order to minimise wait time, my plan is for her to fly LHR->HKG then leave her big suitcase and stay overnight, then HKG->ICN the following day. After staying in ICN for 4 days, she would use the same set of tickets for ICN->HKG, then stay for 8-9 days before flying back HKG->LHR. My wife and I would just get a set of return tickets matching her HKG->ICN and ICN->HKG. My consideration is (1) protect the HKG->ICN in the event of delay on LHR->HKG and (2) obtain the cheapest/most convenient combination. I might have overthought this but is the solution to buy two three separate tickets for one LHR->ICN with longest stopover selectable, one ICN->HKG and one HKG->LHR (but this combination means she will have to drag her big suitcase in Seoul)?

Thanks for the suggestion. Yesterday I tried to reply with the content of my message below on what exactly we try to do but somehow I saw my reply needing moderator approval. Just now and somehow I managed to reply the message below (or abovem don't know how things would be displayed...) without any need for screening (don't know why it went though just now but not yesterday).

So, as explained, the ticket is for our daughter and we try to fit a trip to Seoul in n efficient way. I hope I managed to explain exactly why we are doing it this way.

Many thanks for all the helps.

The answer is a straightforward yes if both LHR-HKG and HKG-ICN are on the same ticket.

When buying separate tickets, there is no obligation on the part of the airline to protect you on the next flight, even if both are on the same airline. Some airlines do provide protection across their own network, but this is not automatic and usually a gesture of goodwill on their part.

Perhaps someone with more experience than myself on CX can confirm how strict CX is in these cases, but I would not rely on that.

My suggestion would be to build in a longer stopover or perhaps invest in a good trip disruption insurance policy.

There is at least one report of CX's permitting short-checking of baggage to HKG on a single ticket which involves an overnight layover:

https://www.flyertalk.com/forum/36200790-post5.html

Book your daughters ticket using the multi-city option. You can specify each leg independently, but it's one ticket which should protect you from tight connections.

Thanks everyone's advice. I also checked with trip.com and CX over chat. It looks like that the only way I can be absolutely sure of guarantee for the flight from HKG to ICN is if I book it from CX website one journey of LHR->ICN (in the case of multicity, still only specify LHR->ICN, and not LHR->HKG then HKG->ICN) then choose an available option that stopover in HKG. In this arrangement, the HKG->ICN would be considered a connecting flight and guaranteed. There appears to be a limited number of options on CX website on the combination/availability of the HKG->ICN flights (they give a number of combinations of both legs, not allowing you to pick each one in turn). In this way, I also need to expect that the check-in suitcase would be flew all the way to ICN (again, my understanding is that we can try to ask for the suitcase to be shipped to HKG but it will depend on the mood and ability of the check-in agent to change it from the default ICN to HKG). Naturally, another option is to plan a stopover of two days before going to ICN. We are weighting these options now.

Many thanks again for all the great advice. I have learnt a lot.