途中(とちゅう)にOn the way, Partway, In the middle of

With 途中(とちゅう) meaning 'on the way', the addition of either the case marking particleに or で will indicate that something is either being done 'on the way to (A)', 'partway through (A)' or 'in the middle of (A)'.

途中(とちゅう) may be seen after verbs in their standard form, or nouns followed by の.

As always, に will put more emphasis on the time or duration of (A), while で will put further emphasis on the process of (A) being the cause of (B), or being used as an opportunity to do (B). Let's take a look at both.

The meanings of で and に in regard to this particular grammar point can overlap quite often, so it may be necessary to see many examples before the slight difference in nuance becomes apparent.