It is rich matter, not simple to discuss in short sentences on a forum especially for me who doesn't master English language like you who makes the points like a lawyer. The fact that no other Asian chess than xiangqi has a river is not a discovery. Shogi is certainly more borrowing to South Asian varieties than from the continent as it has been demonstrated by Japanese historians, Sittuyin/Makruk are obviously descending from Indian varieties as these regions were under strong Indian cultural influence at least until the 13th c., and Janggi is not known in its ancient form so nobody knows if it had a river first or not. I, and Jim Png like me, do not believe that xiangqi is a direct descendent of Liubo, but that there is a link between them. For what I'm concerned I believe I've been clear on that in my books and my website. But I stop to discuss, people want to simplify everything. There are many people now on social networks, Wikipedia, etc., who knows everything at first sight, and say it loud especially against the authors of books who are never sure of nothing. So we are happy that with your "inductive case" it is now clear that Liubo has not influenced the formation of xiangqi. We are progressing and we can go on.
It is rich matter, not simple to discuss in short sentences on a forum especially for me who doesn't master English language like you who makes the points like a lawyer. The fact that no other Asian chess than xiangqi has a river is not a discovery. Shogi is certainly more borrowing to South Asian varieties than from the continent as it has been demonstrated by Japanese historians, Sittuyin/Makruk are obviously descending from Indian varieties as these regions were under strong Indian cultural influence at least until the 13th c., and Janggi is not known in its ancient form so nobody knows if it had a river first or not. I, and Jim Png like me, do not believe that xiangqi is a direct descendent of Liubo, but that there is a link between them. For what I'm concerned I believe I've been clear on that in my books and my website. But I stop to discuss, people want to simplify everything. There are many people now on social networks, Wikipedia, etc., who knows everything at first sight, and say it loud especially against the authors of books who are never sure of nothing. So we are happy that with your "inductive case" it is now clear that Liubo has not influenced the formation of xiangqi. We are progressing and we can go on.