connective N2 uncommon casualpolitewritten
そこで — at that point
そこで
A full written guide for そこで is on the way.
This point is mapped in the grammar tree, but its examples, formation table and usage notes haven't been written yet. The fastest way to learn it now is to meet it in real sentences inside Jengo.
See そこで in real sentences
Jengo shows そこで the way you actually meet it: inside real Japanese sentences, so it sticks instead of staying an abstract rule.
Study it in JengoSources Compiled with reference to A Dictionary of Intermediate Japanese Grammar. Editorial confidence: medium.