If you go to
Alaska's site (the name is
Alaska Airlines, no
n), you will find this if you look for interlining luggage:
https://www.alaskaair.com/content/tr...e/checked-bags
When making international connections on a separate ticket to other airlines within twelve (12) hours of arriving in the connection city, you may follow the baggage allowance and weight restrictions of the international airline - provided a ticketing and baggage agreement is in place between Alaska Airlines and the other carrier.
There are multiple FT threads in the Alaska forum discussing this:
https://www.flyertalk.com/forum/alas...ards-trip.html
https://www.flyertalk.com/forum/alas...g-flights.html