“I scraped the snow off the roof and climbed down, thinking I was now almost home and dry. But I discovered to my dismay that Eiko had woken up and closed the drawbridge door completely. The door doesn’t open from the outside and if I were to try to force it, the noise would probably alert somebody and I’d be seen, and without doubt be suspected of the crime. I’d already killed Ueda and there was no taking that back. And I didn’t want to be arrested before I’d had my chance to kill Kikuoka.
“Locked out and stuck on a windswept roof, I racked my brain for an idea. There was a short rope about three metres long attached to the water tank that a workman had used to climb up the side of the tank. But obviously it was way too short for me to lower myself to the ground. The ladder was only between the level of the drawbridge and the roof. Even if I’d tied the rope to the bottom rung of the ladder, it still wouldn’t have reached the ground. And besides, I’d locked the salon door from the inside earlier, so I wouldn’t have been able to get back into the main building—or into my own room in the tower, again making me an obvious suspect in the killing. Then I realized I still had Golem’s head. I wondered if by using the doll’s head and the three-metre piece of rope, I could find a way into the house. And then I came up with an idea.
“First I tied the rope to the railing that runs around the roof and used it to lower myself to Ms Aikura’s window. I thought if I could make Golem’s head appear to be looking in, and wake her up, she’d be bound to scream. I knew that Eiko had only just closed the drawbridge door so she must still have been awake. If she heard Ms Aikura screaming I knew she’d get up. I would estimate the timing and climb back up to the roof, untie the rope and reattach it to the railing by Eiko’s room window. Then I would make a loud noise right above Eiko’s room, making her get up and come over to the window. I hoped she’d open the window to take a look outside. She’s not afraid of much, that girl, so I thought the chances were pretty good.
“When she didn’t see anything outside, what would she do next? I guessed she’d head to Ms Aikura’s room to find out why she was screaming. If I were lucky, she’d be in a hurry and forget to close and lock the window properly first, and I’d be able to come down the rope and enter through Eiko’s window. Before that I would dispose of Golem’s head from the western edge of the roof as far as I could throw it.
“If Eiko were to go completely into Room 1, I would be able to slip out of Room 2 next door and hurry to let down the drawbridge, pretending that I was rushing across from the tower because I’d heard screaming.
“But if Eiko simply stood talking in the doorway of Room 1, and didn’t go right inside the room, I’d have no other choice but to hide in her wardrobe until morning. Likewise, if she did enter Room 1 but came out again to find me standing on the main building side, lowering the drawbridge, that would be very hard to explain away. Not to mention the possibility that she might not even have opened her window in the first place, or that I could have been spotted climbing in through her window by the Kanais. It was all or nothing, really. My advantage was that I knew my daughter’s personality so well that I felt the likelihood of success was rather good. And then, in the end, it went as smoothly as I could have dared to hope for.”
“Incredible. What a brilliant plan!” said Ushikoshi. “If it had been me, I’d have knocked on my daughter’s window and begged her to let me in.”
“Of course I thought of that too. But I still had so much left to do.”
“Yes, you still had to kill Kikuoka,” said Kiyoshi. “Mr Ushikoshi, if this part of the story has amazed you, just wait until you hear the rest. The planning that went into it is stunning. You’ll be in awe.”
“The murder of Kikuoka… But that happened while I was with Mr Hamamoto. We were definitely together at the time of death, drinking Louis XIII cognac. How on earth did—”
“He used an icicle. When I first arrived at this mansion, and looked up at the tower, it was as I had expected—there were so many huge icicles.”
“An icicle!?”
The detectives looked flabbergasted.
“But it was a knife,” said Okuma. “It was definitely a knife that killed Kikuoka!”
“A knife inside an icicle. He hung a knife from a string under the eaves of the tower roof, and it created an icicle with a knife at the tip. Isn’t that right, Mr Hamamoto?”
“You got it, nicely done! This far north, the icicles are gigantic. Some of them grow longer than a metre. When I’d made my knife-cicles I dipped the tips in warm water to expose the blade of the knife. Then I kept them in the freezer.”
“Ah, so that’s why there was string attached to the knife. Great trick! But…” Okuma broke off.
“Yes, that’s right. But theory and practice turned out to be very different. It wasn’t that easy to turn a hanging icicle with a knife into a weapon. It took me a very long time to perfect it.”
“But why did it have to be an icicle? Or rather, why did you need to attach an icicle to a knife?”
This was the same thing that I was wondering.
“I suppose what I really want to know is, I understand how you made a weapon, but how did you manage to—”
“Well, obviously by sliding it.”
“Sliding it where?”
“On what?”
Several people began clamouring at once.
“Down the stairs of course! As you recall, this mansion has two staircases, one in the east and one in the west wing. If you lower the drawbridge, then there’s a straight line from the window of the kitchen in the tower down to the ventilation hole in Room 14. It becomes one long, steep slide. That’s the whole plan behind the eccentric arrangement of the divided staircases in this mansion.”
“J… Just a minute!”
I couldn’t help interrupting. There was something that was bothering me.
“So you say you slid an icicle with a knife inside down the stairs… But wouldn’t it get stuck on the landings?”
“Why would it? There are twenty-centimetre gaps between the walls and the south end of each of the landings.”
“So you could be sure that the icicle would pass through those gaps at the end of each landing? But the staircases are pretty wide. Surely you couldn’t predict the exact course the knife would take? What if it had slid down the centre of the staircase? How could you make sure it stayed over… to the… side… Oh, I get it!”
“That’s right. That’s the only reason that I built this house on a slant. If the house is sloping to one side, then it follows that the stairs are too. This long staircase slide, to exaggerate a little, becomes a kind of V shape between the staircase and the wall. The house leans towards the south, so the knifecicle was sure to travel down the southern edge of the stairs.” (See Fig. 9.)
“Wow!”
I wasn’t the only one lost in admiration. If Eiko had been here too, what kind of praise would she have been heaping on her beloved father right now?
Ushikoshi took over the questioning.
“So the icicle would have definitely slid through that twenty-centimetre space at the end of the corridors… I would never ever have imagined that someone could build a whole house with the sole purpose of killing another human being. Especially one so crooked… And then, Mr Hamamoto, you are saying that the icicle entered Room 14 through the ventilation hole?”
From here, Ushikoshi began to sound a little pained.
“You experimented over and over to make sure the hole was in the exact right position, so that you could place the icicle at the top of the drawbridge and have it fall without any extra force straight down into Room 14.”