Originally Posted by Kiwi Flyer
The order BP was issued - so sequence number 1 is the first BP for that flight (on that day), 2 is the second, etc.
A little correction: it is the order of which passengers check in (via phone, internet, or counter), rather than the order of BP was issued - you can i-check first but BP issued much later upon arrival at airport and still get seq. no. 001.