diff --git a/day09.go b/day09.go
index ffb3d82..b2a6497 100644
--- a/day09.go
+++ b/day09.go
@@ -30,10 +30,6 @@ func nextOasis(previous int, start []int) int {
 	return current + nextOasis(current, levelBelow)
 }
 
-func previousOasis(previous int, start []int) int {
-	return 0
-}
-
 type day09 struct{}
 
 func (d day09) solve1(r io.Reader) string {