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02:49:18 / BACKUP RECORDER
GONG GONG
CHIME-GONG CHIME-GONG CHIME-GONG
CHIME CHIME CHIME CHIME
Kenji
In the empty recording studio, only the clock chimed the time...?
And that clock is now gone.
And that clock is now gone.
Appraiser
Let's analyze the sound first.
In the dark, our ears can sometimes be more honest.
In the dark, our ears can sometimes be more honest.
CASE FILE 35 Twelve Chimes Left in an Empty Room
- Setting: Live streaming studio for a luxury watch auction
- Missing item: Minute Repeater with two gongs, valued at 120 million yen, using a common quarter-hour system
- 2:49 AM: Chime sound recorded during an unmanned acoustic test. The watch remained in the video until just before the screen went dark.
- 2:54 AM: Camera inside the display case went dark for 70 seconds.
- 2:58 AM: Shiraishi, the live stream director, left with a silver equipment case.
- Shiraishi claims it was "an empty case after the cables were removed."
- 3:00 AM: The watch was confirmed missing from the display case.
① 70 seconds of lost footage. The "sound" that remained before it.
Backup Recording Timeline
| 2:30 AM | Watch synchronized to the facility's master clock, continuous recording began. |
|---|---|
| 2:49:18 AM | Unmanned acoustic test. Three types of chimes recorded. The watch remained in the video thereafter. |
| 2:54:02 AM | Camera inside the display case went dark. |
| 2:55:12 AM | Video returned. Visually, no abnormalities on the pedestal. |
| 2:58 AM | Shiraishi passed through the weighing gate carrying a silver equipment case. |
| 3:00 AM | Storage security manager confirmed the watch's disappearance. |
*The weight of equipment cases varies depending on their contents, so this gate was not an alarm system to stop removals for small discrepancies, but rather operated as an audit log for later verification.
Kenji
If it was stolen during the blackout, wouldn't the 2:49 AM sound be meaningless?
Appraiser
The opposite.
That sound marks "how long the watch was there."
That sound marks "how long the watch was there."
② A minute repeater "translates" the time into sound.
Appraiser
A typical two-gong minute repeater, when activated, first chimes the hours, then the quarter-hours, and finally the remaining minutes.
This particular watch chimes the time shown on its dial when the operating lever on the side of the case is moved all the way and released.
This particular watch chimes the time shown on its dial when the operating lever on the side of the case is moved all the way and released.
Low tone = Hours / Double tone = Quarter-hours / High tone = Remaining minutes
You can tell the time displayed on the watch from the order and number of chimes, even without looking at the dial.
Kenji
It's like the voice-over function for watches.
But it doesn't use batteries or speakers.
But it doesn't use batteries or speakers.
③ Two low tones, three double tones, four high tones. The answer is 2:49.
Deconstructing the recorded sound
| Sound | Number of chimes | Meaning |
|---|---|---|
| Low single tone | 2 times | 2 o'clock |
| High-low double tone | 3 sets | 15 minutes × 3 = 45 minutes |
| High single tone | 4 times | 4 minutes past 45 minutes |
2 o'clock + 45 minutes + 4 minutes = 2:49
Counting each chime in the double tones, the hammer struck a total of 12 times.
Kenji
I see. It chimed twelve times, but the answer isn't twelve o'clock.
Appraiser
It's not a game of adding up all the chimes. The type and order of the sounds are the grammar.
④ Three suspects: those who handle sound, keys, and video.
Suspect A: Maki Sakakibara
34 years old, sound engineer
Manages contact microphones, ambient microphones, and the playback console. Testified that "no pre-recorded audio was played." Was in the audio control room during the blackout.
Suspect B: Makoto Odagiri
51 years old, head of storage security
Manages the master key for the display case. Confirmed time synchronization and start of recording at 2:30 AM, then returned to his patrol.
Suspect C: Ren Shiraishi
38 years old, live stream production director
Supervised camera placement and equipment removal, and was issued a production key valid until 3:00 AM. Carried a silver case at 2:58 AM but claims it "was empty."
Shiraishi's testimony:
"That silver case contained streaming cables. I left the cables in the studio, so the case was empty when I left. The 2:49 AM sound must have just been Ms. Sakakibara playing a pre-recording. You can't say the watch was there just because there was sound."
"That silver case contained streaming cables. I left the cables in the studio, so the case was empty when I left. The 2:49 AM sound must have just been Ms. Sakakibara playing a pre-recording. You can't say the watch was there just because there was sound."
⑤ "The person who managed the sound is the culprit" is too soon.
Kenji
She can record, play, and edit sound.
Ms. Sakakibara can do all of it!
Ms. Sakakibara can do all of it!
Appraiser
What she *can* do and what she *did* are different.
Sound alone cannot rule out recorded playback, a different watch, editing, or a discrepancy in the displayed time. Since the chimes are on a 12-hour cycle, sound alone cannot determine if it was AM or PM.
Sound alone cannot rule out recorded playback, a different watch, editing, or a discrepancy in the displayed time. Since the chimes are on a 12-hour cycle, sound alone cannot determine if it was AM or PM.
What can and cannot be determined from chime sounds alone
| Highly likely to be known | Cannot be known independently |
|---|---|
| If it's a common quarter-hour system, the mechanism read the display as 2:49. | The actual precise time. |
| If it's a normal type, some operating action was applied. | Whether it's AM or PM. |
| Pitch and intervals are similar to prior recordings of the individual watch. | Whether it's recorded playback or live sound, the watch's location, the operator. |
⑥ The watch didn't chime on its own. A pre-set jig made it chime.
Appraiser
This particular watch is not an alarm, nor a sonnerie that automatically chimes when the time arrives. It's a standard minute repeater.
However, for this unmanned acoustic test, a dedicated jig for this model was programmed to activate the operating mechanism once at 2:49 AM.
However, for this unmanned acoustic test, a dedicated jig for this model was programmed to activate the operating mechanism once at 2:49 AM.
Kenji
No one chimed it. But it wasn't that nothing chimed it.
Important Premise:
This jig is a fictitious device unique to this story, and its settings were adjusted by a specialized technician based on the operating procedure of the model. It's not a modification that makes the watch automatically chime, but an external device that substitutes for human operation once.
This jig is a fictitious device unique to this story, and its settings were adjusted by a specialized technician based on the operating procedure of the model. It's not a modification that makes the watch automatically chime, but an external device that substitutes for human operation once.
⑦ Three microphones and jig logs ruled out "playback from the console."
Original data from 2:49:18 AM
- Contact microphone directly connected to the base detected mechanical vibrations first.
- Left and right ambient microphones recorded the same chimes with slight delays corresponding to their distances.
- Playback console and studio speaker output history show zero.
- The dedicated jig's position sensor recorded one full cycle of the operating mechanism.
- Pitch, chime interval, and decay pattern are consistent with the chime verification of the same watch at 2:30 AM.
- There is video footage of the watch functioning normally, synchronized to the master clock at 2:30 AM.
- From the end of the chimes until 2:54:02 AM, the watch was visible in uninterrupted original footage.
Appraiser
Contact vibrations, ambient sound, and the jig's movement all coincide at the same instant. Playback from speakers via the console would not have this time difference and sequence.
Therefore, at 2:49:18 AM, the watch was still on the pedestal.
Therefore, at 2:49:18 AM, the watch was still on the pedestal.
Kenji
The sound didn't tell us who the culprit was.
It narrowed the time of the theft down to 70 seconds.
It narrowed the time of the theft down to 70 seconds.
⑧ The blackout was not a communication error, but black foam covering the lens.
Evidence of the 70-second video blackout
- During the blackout, camera power, time signal, and video data volume were maintained.
- The first and last few frames show a soft black material approaching the lens.
- A piece of black sound-absorbing foam with a silver adhesive layer was collected from the corner of the display case pedestal.
- Shiraishi's silver case interior has a missing section of the same shape.
Kenji
Black foam, silver backing. It's the same as Shiraishi's case.
Appraiser
The color alone isn't enough.
Next, let's look at the torn cross-section and the weight.
Next, let's look at the torn cross-section and the weight.
⑨ The "empty case" was 270 grams heavier.
Exit weighing gate and re-weighing of the case
| Tare weight registration before loading | Empty case weight: 5.420kg |
|---|---|
| Passage record at 2:58 AM | 5.690kg |
| Difference | 270g |
| Watch + protective capsule | 268g as per setup records |
| Foam cross-section | The fragment from the pedestal and the missing part of the case are continuous in terms of bubbles, adhesive layer, and tear. |
Appraiser
The weighing error is ±2 grams. A difference of 270 grams cannot be called "empty."
Furthermore, the foam that covered the camera is a piece torn from this very case.
Furthermore, the foam that covered the camera is a piece torn from this very case.
Kenji
It wasn't the case that was empty, it was his explanation.
⑩ Crime Reenactment - Five minutes after the chimes ended, the watch was hidden in 70 seconds.
Shiraishi's actual movements
- Waited until the unmanned test ended at 2:49 AM. If stolen before the chimes, the lack of sound would immediately indicate an anomaly.
- At 2:54 AM, peeled off some sound-absorbing foam from inside the silver case and covered the camera lens.
- Opened the display case with the provided production key and placed the watch, still in its protective capsule, into the false bottom of the silver case.
- After 70 seconds, removed the foam. Left only a black cushion on the pedestal that resembled the watch from a distance.
- Claimed it was "an empty case after the cables were removed" and proceeded to the usual equipment removal route.
- However, the weighing gate recorded 270 grams, matching the watch and protective capsule.
Appraiser
Shiraishi knew the blind spots in the live stream footage.
But even if he could black out the screen, he couldn't erase the sound and the weight.
But even if he could black out the screen, he couldn't erase the sound and the weight.
⑪ The culprit is Ren Shiraishi, the live stream director.
The 2:49 AM sound didn't reveal the culprit, but testified that "the actual item was on the pedestal at that time."
Appraiser: "The chime sound alone didn't make you the culprit. The sound indicated that the watch was on the pedestal until 2:49 AM. The 70-second blackout, the torn foam from the case, and the 270-gram weight difference identified the case that removed the watch after that."
Appraiser
Please open the false bottom of the silver case.
If it's empty, there's no reason to hesitate.
If it's empty, there's no reason to hesitate.
Shiraishi's confession:
"An overseas intermediary told me that security wouldn't suspect production staff before the broadcast. I was offered an amount that would clear my debts, and I thought I could get past inspection with an equipment case. If I waited until the acoustic test finished, the discovery would only happen right before the broadcast."
"An overseas intermediary told me that security wouldn't suspect production staff before the broadcast. I was offered an amount that would clear my debts, and I thought I could get past inspection with an equipment case. If I waited until the acoustic test finished, the discovery would only happen right before the broadcast."
Kenji
He stole it after it stopped chiming, but the record of it chiming caught up to him.
Appraiser
Even if the sound disappears, the timeline remains.
After the incident, Kenji starts chiming "2:49" with a coffee cup.
Kenji
GONG, GONG. CHIME-GONG three times. Finally, CHIME four times.
Appraiser, I've become a minute repeater too!
Appraiser, I've become a minute repeater too!
Appraiser
It's 10 AM.
Kenji
Then I just need to keep chiming for about seven hours and eleven minutes to catch up.
Appraiser
(I want to soundproof the break room before the clock...)
Conclusion: The chime sound and continuous video proved the fact that "the real item was there until before the blackout."
Appraiser
A minute repeater is a complex mechanism that generally chimes the hours, quarter-hours, and remaining minutes with different sounds, indicating the displayed time even in the dark. It usually only activates when requested and does not chime automatically just because the time has arrived.
In this case, an external dedicated jig automatically activated it at 2:49 AM. Two low tones, three sets of double tones, and four high tones indicate that the mechanism read the time as 2:49.
However, sound alone cannot determine whether it was AM or PM, whether the actual time was correct, whether it was live sound or playback, or who removed it. By combining the original recording, multiple microphones, jig logs, and prior time synchronization, we confirmed that the watch was on the pedestal until 2:49 AM.
Finally, by overlaying the 70-second blackout, the foam's cross-section, and the 270 grams from the weighing gate, we disproved Shiraishi's testimony of an "empty case."
The sound didn't point to the culprit. Combined with the continuous video, it showed the fact that the watch was on the pedestal until before the blackout.
In this case, an external dedicated jig automatically activated it at 2:49 AM. Two low tones, three sets of double tones, and four high tones indicate that the mechanism read the time as 2:49.
However, sound alone cannot determine whether it was AM or PM, whether the actual time was correct, whether it was live sound or playback, or who removed it. By combining the original recording, multiple microphones, jig logs, and prior time synchronization, we confirmed that the watch was on the pedestal until 2:49 AM.
Finally, by overlaying the 70-second blackout, the foam's cross-section, and the 270 grams from the weighing gate, we disproved Shiraishi's testimony of an "empty case."
The sound didn't point to the culprit. Combined with the continuous video, it showed the fact that the watch was on the pedestal until before the blackout.
Minute Repeaters Learned from the Incident
- The order of sounds has a grammar: In the common system, it chimes hours, then quarter-hours, then remaining minutes.
- 2:49 is 2-3-4: Two low tones, three sets of double tones, four high tones.
- Usually on-demand: Different from sonnerie which chimes automatically when the time arrives, or alarms that chime at a set time.
- Chimes the displayed time: If the watch is off, it will chime the incorrect displayed time, not the actual time.
- Do not determine location or person from sound alone: Exclude playback, different watches, editing, and accidental activation with other evidence.
- Systems vary by model: Decimal repeaters, carillons, etc., have different chime sequences.
*This story is a fiction where a "common quarter-hour, two-gong minute repeater was activated once by a fictitious acoustic test jig unique to this story." It does not depict officially approved equipment from actual manufacturers. Operating parts, chiming methods, number of gongs, and safety mechanisms vary by model. For actual watches, always operate the mechanism correctly and fully, avoid re-activating it before the chimes are complete, avoid time adjustment during or immediately after chiming, and always follow the instruction manual or official service guidelines. Operating with tools or general-purpose jigs can cause malfunctions or external damage.
Deduction Points This Time
- The 2:49 timestamp was broken down into "2 o'clock + 45 minutes + 4 minutes"
- The culprit was not identified by sound alone; actual sound was proven by contact vibration, airborne sound, and jig logs.
- The actual sound at 2:49 and the continuous video up to the blackout were overlaid, narrowing down the possible theft time to 70 seconds.
- The cross-section of the foam and the 270-gram weight difference led to the false bottom of the silver case.
- Do not confuse minute repeaters, sonnerie, and alarms as the same "chiming watches."
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