Line to toe in Rochester (4)

I believe the answer is:
oche
'line' is the definition.
(I've seen this before)
'toe in rochester' is the wordplay.
'OCHE' is hidden within the letters.
However, I am unsure how the hidden word is indicated.
'to' is the link.
Can you help me to learn more?
(Other definitions for oche that I've seen before include "Behind which a darts player must stand" , "sporting line" , "Dart-playing line" , "Line from which dart-players throw" , "front line" .)
