From Altstätten it starts, past the inn on the left and uphill at the edge of the forest. Cross a bridge and walk through a swathe diagonally to the right for free pastures, You climb up in the left part of this middle-steep slope. At the top, below the forest, you walk into the top right corner of the open ground.
Now you climb a steep path on the left through a short forest belt. Then you follow the again path up to the second ridge, which drops steeply to the east. Here you can take a short break in front of a small shingle hut and see the summit of the Sonnenkopf on the right already. Now it goes over the mountain ridge high to Gipfelkreuz.
The descent is the ascent. If you are familiar, you can also go down the pastures north of the usual route.