第9堂：引征斷
https://gogo1.teachable.com/courses/10/lectures/43110868
https://www.101weiqi.com/chessbook/notation/40873/
https://www.101weiqi.com/chessbook/notation/40876/
https://www.101weiqi.com/chessbook/notation/40875/
https://www.101weiqi.com/chessbook/notation/40874/
https://www.101weiqi.com/chessbook/notation/40870/
https://www.101weiqi.com/chessbook/notation/40871/
https://www.101weiqi.com/chessbook/notation/40866/
https://www.101weiqi.com/chessbook/notation/40877/
https://www.101weiqi.com/chessbook/notation/40880/