From what I remember, you need to exchange a rune stone with Rune to get bolt cutters. You can then use the bolt cutters to open the passage.
Since this comment was ~4 months ago, I'm assuming you already got it or dropped the search. But just in case, the second rune is found during the sign puzzle right before the lamp post puzzle. The hint is to turn both signs that say "Secret" so that it follows a direction, one opens a path for a coin and another for a rune.