Unclear statement   Just before the Vietnam invasions stuff the article reads During Kublai Khans reign he was put under pressure by many of his advisers to further expand the territory of the Yuan through the traditional Sinocentric tributary system However they were rebuffed This makes it seem as if the advisors were rebuffed but I think Khubilai did actually try to expand the tributary system to Japan I think what was actually rebuffed were the attempts to establish more tributary relationships so maybe someone with better knowledge than mine could look into it