Descend Mt. Nozuko and climb the next Mt. Mikan. You will see a steel tower at the summit. This steel tower is the summit of Mt. Karuno. Climb as hard as you can!
It is hard to find a gap between the mandarin trees, so we wander from place to place to get to the top. When you see the monorail, you are at the entrance to the mountain. Follow the rest of the footprints and you will reach the steel tower square. There was also a sign for Karunoyama.
