Finally found my answer
http://www.airchina.co.uk/en/managem...assengers.html
22.1 Transportation between China and Japan, to/from Americas
First Class or Business Class passengers are allowed up to two pieces of baggage free of charge, each weighing no more than 32kg (70 lbs) and the total linear dimensions of each baggage shall not exceed 158cm (62 inches).
Economy Class passengers are allowed up to two pieces of checked baggage free of charge, each weighing no more than 23kg (50 lbs), and the total linear dimensions of each shall not exceed 158cm (62 inches).
Each infant is allowed one piece of checked baggage free of charge, and its total linear dimensions shall not exceed 115cm (45 inches). An additional folding stroller or cradle may also be checked free of charge for each infant.
If Air China operates a flight between Japan and any Continent (via China), then above rules on the Free Baggage Allowance will also apply.
46kg + 5kg carry on + stroller
Very nice, very unexpected perk.^