Defeat Zhang Fei and Guan Yu within 10 minutes. Item spawns at the bottom
right of the main castle next to the guard post. Item: Ruby/紅玉
Method: Another not so difficult treasure to get. First defeat the guy at the
southern entrance to open the path to Edo Castle. (You could alternatively,
go from the western entrance too) Then, keep moving until you reach a place
with an officer guarding a door near the eastern entrance. If you check you
map, you’ll see that behind the door would have 3 officers (2 Chinese and 1
snake officer) and Zhang Fei at the end of the path. Defeat the guy at the
door and go straight to Zhang Fei. You can defeat the others along the path
to make your battle easier later.
When you defeat Zhang Fei, the doors to the main keep will open. Go enter the
main keep. You can defeat anyone in your path to make your exit later easier
as the castle will be set on fire. Follow the path to the second floor and
defeat Guan Yu. As soon as the gate behind him opens, the item report will
appear.