After the battle against the Ceremony Master Kurosawa (and for the final battle against Kusabi), you may be tired and do not want to use any Healing Herbals or Holy Water in the long underground passage. You must not fight the enemies there. You can walk until an enemy appears then run back to spiral corridor. Then, go back to underground passage. The enemy should have disappeared. Continue ahead, and if an enemy appears, repeat the process. In this underground corridor, there is a place with an "S" shape. If you meet enemies after this place, go back to the "S" passage until the enemy disappears. You will finally arrive at a place where the enemy appears at your back. Do not look back. Just run to the ceremony place to fight the Kusabi. Note: There is one mirror stone in the underground passage.