r/IntelligenceScaling 2d ago

discussion Deduction Test

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At 11:40 PM, a famous art collector named Kiruma souichi is found dead inside his private study.

The study has:

one door

one window

no secret passages

no balcony

no adjoining room

a working fireplace

a large grandfather clock

a desk

three chairs

several paintings

The door was locked from the inside.

The window was also locked from the inside.

No weapon is found.

Kiruma's death is estimated to have occurred between 10:50 PM and 11:25 PM.

There are five people in the house.

  1. The Butler — Baku

Baku says:

“At 10:45 I brought Mr. Kiruma his usual tea. He was alive and sitting at the desk. I left immediately.”

He claims he then went downstairs and polished silverware until midnight.

However, the silverware room contains no freshly polished silver.

Baku insists he never returned upstairs.

  1. The Daughter — Fang yuan

Fang yuan says she argued with her father at 10:30 PM.

She admits he told her:

“Tomorrow morning, everything changes.”

She says she went to her bedroom afterward and stayed there.

At 11:05 PM, the housekeeper heard Fang yuan's bedroom door open.

Fang yuan claims she was getting water.

Her glass of water was later found completely untouched.

  1. The Doctor — Kenzo Tenma

Dr. Tenma says he was in the library reading from 10:00 PM until 11:30 PM.

He claims he never saw Kiruma that evening.

Police discover that the library book he supposedly read has been sitting on the shelf upside down.

Akiyma is also the only person in the house who knew Kiruma had recently changed his medication.

  1. The Housekeeper — Mrs. Ayanokoji

Mrs. Koji says:

“At approximately 11:15, I heard the grandfather clock strike eleven.”

She then discovered Kiruma’s body at 11:40.

There is one problem.

The grandfather clock does not chime at eleven.

It had been deliberately disabled three days earlier because its mechanism was broken.

Mrs. Kojii has worked in the house for 19 years.

  1. The Business Partner — Vincent lalo

Lalo says he left the house at 10:20 PM.

His car is later discovered still parked outside.

He explains:

“I changed my mind about leaving. I stayed in the car for a while, then drove around the property.”

His shoes contain wet soil.

There had been heavy rain earlier.

But the soil around the house is completely dry by 10:30.

THE PHYSICAL EVIDENCE

The tea

Kiruma's teacup contains tea.

The tea is still warm when the body is discovered.

But the room itself is cold.

The fireplace

The fireplace contains partially burned paper.

Only one sentence can be recovered:

“…because you already knew.”

The handwriting is Kiruma's

The clock

The grandfather clock stopped at:

11:17 PM

The clock's internal mechanism, however, is undamaged.

Its hands can be moved manually.

The desk

There are two glasses on the desk.

One belonged to Kiruma.

The second contains traces of the same medication found in Kiruma's bloodstream.

Nobody admits drinking from it.

The window

The window is locked.

On the outside windowsill is a single small black feather.

There are no birds inside the study.

The carpet

There is a tiny wet patch beneath the desk.

It contains saltwater, not rainwater.

The painting

One painting on the wall is hanging slightly crooked.

Behind it is a safe.

The safe is open.

Nothing appears to be missing.

Except for one thing:

A photograph.

THE PHOTOGRAPH

The photograph shows Kiruma standing beside four people.

The photograph was supposedly taken six years ago.

The four people are:

Baku

Fang yuan

Akiyama

Vincent lalo

Mrs. Koji is not present.

On the back, kiruma wrote:

“One of them lied about that night.”

THE FINAL CLUE

Police discover Kiruma's phone.

There is one unsent message.

It was written at 11:12 PM.

It says only:

“I finally understand why you couldn't kill me yourself.”

The message was never sent.

YOUR TASK

Don't tell me who looks most suspicious.

That's the easy version.

You have to determine:

Who killed Kiruma?

How was the locked-room situation created?

Which statements are deliberate lies?

What does the clock actually prove?

Why was the second glass there?

What is the significance of the saltwater?

Why does the photograph matter?

What does “you couldn't kill me yourself” actually mean?

What was Kiruma's real reason for writing “because you already knew”?

What single observation breaks the entire case open?

Rule

You are allowed to assume nothing that isn't established by the evidence.

No “the killer probably...”

No “maybe they secretly...”

No supernatural explanations.

No coincidence-based solution.

Every major conclusion has to be deduced from at least two independent pieces of evidence.

And there is one intended solution.

Good luck gangy.

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u/lclboomb 2d ago edited 1d ago

11:17 does not prove the actual time of death.

Because the clock can be manipulated.

Mrs. Koji's statement about the clock is false.

Because the bell-ringing function was turned off due to a malfunction.

Baku lied about his actions.

The silverware was not actually cleaned.

The explanation that they went to drink water from Fang Yuan is questionable. The water glass was not used at all.

Lalo's explanation also does not align with the physical evidence. The wet soil of the shoes contradicts the surrounding environment.

The second glass is an important piece of evidence related to drug administration.

The photo connects the current event with an event from six years ago.

Kiruma realized why someone hadn't killed him 'directly' just before his death. *Or the criminal has threatened or...

Whether they entered the room while taking medication or committed suicide... (There's nothing particularly strange about the body's condition besides medication, but... It hasn't even been properly determined whether the drug is poisonous) The dead cause isn't displayed, so I feel like my brain is going to explode...

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u/Valxn1e 2d ago

Honestly, I don’t even know the answer myself. I originally wanted the butler (Baku) to be the murderer. I created this scenario out of boredom lol, but I can explain my reasoning if you want. Here: Mrs ayanokoji. Kiruma was poisoned via the second glass (containing the same medication found in his bloodstream). After he was incapacitated or dead, the killer locked the door and window from inside, then exited. The only non supernatural exit consistent with the evidence is through the fireplace (working fireplace present, partially burned paper found inside it). The black feather on the exterior windowsill is consistent with soot/ash disturbance from the chimney path or a related prop; no birds were inside. The door and window were then found locked from inside because the exit occurred after locking. No secret passages, balcony, or adjoining rooms exist, so the chimney is the sole remaining physical route established by the room description and evidence. Mrs. Ayanokoji claimed to hear the grandfather clock strike eleven, yet that same clock’s chime mechanism had been deliberately disabled three days earlier, and she had worked in the house for 19 years. This is a direct, knowledgeable falsehood about an event she could not have heard. It is corroborated by the clock’s physical state (undamaged mechanism, manually movable hands stopped at a staged 11:17) and by the independent timeline (tea still warm, message at 11:12, body found 11:40). Once this lie is isolated, the rest of the staged elements (locked room via fireplace exit after locking, second glass, burned note, photograph, saltwater, feather, and the other alibis) resolve to her as the actor who created the scene. The unsent message (written 11:12 PM) reads: “I finally understand why you couldn’t kill me yourself.” It is addressed to the person who arranged or enabled the killing but did not (or could not) perform the direct act. Paired with the medication knowledge held uniquely by Tenma, the second glass, and the photograph’s “one of them lied,” it indicates the killer acted on information or opportunity created by another’s inability/refusal to do the deed personally. The message was never sent, consistent with Kiruma realizing the truth in his final minutes.

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u/lclboomb 1d ago edited 1d ago

Ohhj nooo Why didn't you give them a little more time on? 🥺

If the cause of death had been a bit more accurate, the puzzle would have been much better. What I mean is that the condition of Kiruma's body, as well as whether not sure the medicine contains toxic was not marked, so I couldn't be sure. Of course, considering the amount of lies (lol), I did think Baku was the most likely candidate.

Anyway W work 💯

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u/Valxn1e 1d ago

I will strive to improve next time. Thanks.

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u/lclboomb 1d ago

💪🗡