After an interval of 6 years, the Japanese Guidelines for the Management of Stroke were revised in 2015 in accordance with recent advances in clinical knowledge. The chapter on subarachnoid hemorrhage includes new and revised recommendations for diagnosis, treatment selection, and management of vasospasm. The chapter on diagnosis recommends re-examination of vascular images at regular intervals in cases in which cerebral aneurysm was not detected on the first examination. The section dealing with treatment selection for cerebral aneurysmal emphasizes that the method for aneurysm obliteration should be selected based on consultation with both surgical and endovascular specialists. The role of triple-H therapy(i.e., induced hypertension, hypervolemia, and hemodilution) has changed from a preventive measure to a treatment option for symptomatic cerebral vasospasm.