It is possible that all these Chinese populations are part of O. sinensis, but the Laos specimens are relatively large, similar to O. latipes rather than the tiny O. sinensis. The east Korean population is part of a clade with O. sakaizumii and O. latipes. Based on morphology it is closer to O. sakaizumii than O. latipes, but it may be an undescribed species.
It's possible that all the Chinese populations belong to the same species (O. sinensis), but the Laos specimens are larger and more similar to O. latipes than the tiny O. sinensis. The east Korean population is part of a group with O. sakaizumii and O. latipes, based on morphology it's closer to O. sakaizumii than O. latipes, but it might be a new species.