forms the iron pillar, a solid connection of two stones, mostly directed from side to centre.
The iron pillar can work well in a position like this, where Black is attacking on the left and making territory on the right. It removes all White's sabaki tactics here.
The iron pillar can be fine on its own, as well. Here it turns an influential san-ren-sei into a more territory-oriented framework, by making a third lineinvasion difficult, as White cannot attach to the side stone, applying sabaki tactics immediately.
This move is also known as burasagari