Ivanka Trump attends Abe meeting, page-18

Makes alot of sense for Trump on many levels:

1. Its an indirect stick-it to the current POTUS - already engaging world leaders before taking office.
2. Its an assertion of power for his soon to be caucus and to the Republican party as a whole. The President of Japan came to Trumps House for tea FFS!
3. It improves the marketability of Ivanka and raises her profile on the world stage, especially in Japan, where she could launch a line of Trump branded Kimonos if she so wished. Im sure Trump will have Ivanka playing some kind of role in the White Office
4. Because its not a formal meeting they can talk about whatever the hell they want, whether its dodgy backdoor deals, nukes etc, ya know all the "unimportant stuff"
5. Having an attractive personable (bit IMHO two faced) woman in a meeting never hurt relations, especially considering Japanese men's attitudes towards blonde women (generalisation yes but I think its an accurate one).