No Passing on the Right-hand Portion of the Road for Overtaking
追越しのための右側部分はみ出し通行禁止(おいこしのためのみぎがわぶぶんはみだしつうこうきんし)
Meaning
A sign prohibiting driving onto the right-hand portion of the road in order to overtake. Overtaking itself is possible as long as you do not cross into the right-hand portion.
Common mistake on the test
Must be distinguished from 'No Overtaking' (with an auxiliary sign). This sign does not prohibit overtaking that stays out of the right-hand portion of the road.