Why was the "piece concept" of baggage applied on an Australia-Japan flight?

Question

There are two ways to define baggage allowances on flights. IATA:

• Weight Concept: measured by the total weight of checked-in baggage, which is shown as a weight amount on the ticket (e.g. 20 kg or 45 lb).
• Piece Concept (PC): measured by the number of pieces of checked-in baggage (shown as PC on the ticket).

Until last week, I had never had or even heard of the "piece concept" being applied outside flights to/from the US, with essentially the entire rest of the world using the "weight concept".

However, when flying from Japan to Australia with ANA, at check-in I was told my 25 kg bag exceeded the 23 kg piece limit and I would have to pay a surcharge for the extra weight. The same bag had been accepted without question on three previous flights during the same trip, all of which were also to or within Japan.

I initially assumed the check-in person was mistaken, but much to my astonishment the fine print of my ticket did indeed say BAGGAGE: 2PC, instead of the expected BAGGAGE: 30KG. Why?

The only reason I can think of: I purchased the ticket off ANA's international website, priced in USD, so I presume this somehow triggered it into applying the piece concept. But this still makes no sense, because the piece concept is (in my limited understanding) an FAA requirement/standard and not applicable to either origin or destination here.

(In case you were wondering: in the end the surcharge was waived, because our group combined had a 9 piece allowance (thanks Star Gold) and we used only three of it.)

Answer 1

As mentioned in a comment, this seems to be ANA regular luggage allowance, not something specific to this flight or the way you booked your ticket. I thought airlines in Europe actually combined both restrictions but after double-checking, it seems they also apply the “piece concept”: BA, Lufthansa, KLM. So it's definitely not restricted to the US.

Incidentally, 23 kg / 50 pounds is roughly the upper bound for a weight that can be lifted safely with two arms (e.g. NIOSH lifting equation). That's only true under ideal conditions (which are unlikely to be met when loading a plane) and you can easily find other industries breaking that rule but heavier bags definitely require special handling, at least in theory. That may be an additional rationale for airlines to use that limit and require a surcharge or premium fare for heavier bags.

For all these reasons, the most practical advice is to assume that anything over 23 kg could be an issue and to double-check the fine print if you need more.