Warikomi is a move wedging between two enemy stones.
BobMcGuigan The move above is also an example of hanekomi, a warikomi which is, at the same time, a hane.
A warikomi is often a tesuji used to create cutting points or separate the opponent's stones. For example:
is the warikomi.
This example is from the tesuji dictionary by Segoe Kensaku and Go Seigen.
HolIgor comments.
I was taught that it is to your disadvantage to play between two stones separated by 1 space. I followed this rule to discover later that this is not always true and as the stones appear on both sides of the one-point jump formation you have to consider seriously a probability of a cut. At some point the motto of the day was "Check your connections".
Get good connections, trust your connections but check them.