From Ni-Rensei (two star points) to San-Rensei (three star points)…
Lets have a look, how San-RenSei can be played by some alternatives (4 variations) and how Black can prevent white to answer with San-Rensei. Herefore we start with the Two star points opening, so called Ni-Rensei.
Usually, black’s aim in this Ni-RenSei fuseki is to play a fast paced game. White’s first two moves can be anything basically but here we are especially interested in a white ni-rensei as well because this fuseki pattern is quite popular recently.
I have put together the different options in one SGF, how black can play from this Two star points further on which I found on Gobase.org. (Rec.: Tks to Milton N. Bradley for the request and Jan van der Steen.)
Various strategies are possible from the position shown in the first diagram. Black can enlarge his area of control with A or immediately build a moyo with B (which would create a so-called san-rensei pattern).
Alternatively, black can make the game small-scale by approaching white’s position from the inside with C or D. Although various other moves have been played in this position the final move which is explicitely shown is black E. (Source: Gobase.org (C) Milton N. Bradley)