:
This move was found by me in 2007. In the meantime, it has been approved by Prof. Jeong SooHyun 9p, and has been also used by Cheng Xiaoliu 6p in his 2010 solution. It gives Black an advantage of one point in Capture Variation, and of two points in the Semeai Variation. Additionally, it pre-empts a white ko-threat in this area.

We will keep naming this move "second" throw-in throughout this book (despite it is the first one in our solution), due to the sequence of the modern professional solution.