rating: +2+x

Item #: SCP-2048-JP

Object Class: Safe (Provisional)

Special Containment Procedures: SCP-2048-JP is to be stored in a low-risk item storage locker at Site-8107 and is not to be allowed to be removed except during testing.

Description: SCP-2048-JP is a Japanese 10-yen coin that has a specific probability (hereafter designated as SCP-2048-JP-1) that it lands head-side up when flipped. It was previously registered as an Anomalous item as "a 10-yen coin that always lands with its head-side facing up", until it was accidentally dropped during a routine examination on 2020/04/01 and landed with its tail-side up. Following the results of Test Series 2048-JP-1 described below, the item has been newly documented as SCP-2048-JP.

Test Log 2048-JP: This series of tests was conducted to determine the exact nature of SCP-2048-JP.

Test Log 2048-JP-1 – Date 2020/04/03

Conducted by: Dr. Mochizuki

Subject: SCP-2048-JP

Method: D-1902 is instructed to flip SCP-2048-JP and then record on an electronic recording medium which side was facing up when it landed. This procedure is repeated 4000 times. In order to prevent any tampering attempts, a surveillance camera is used to monitor D-1902's actions and the coin surface, which is constantly compared to what is inputted into the electronic storage medium.

Result: The following results were obtained. Detailed test records are available in Appendix.

Analysis: It is clear that SCP-2048-JP-1 fluctuates with number of trials. As the number grew, SCP-2048-JP-1 was observed to decrease and then increase again. This phenomenon is assumed to be recurring.

Coin surface / Number of trials 1 ~ 500 501 ~ 1000 2001 ~ 2500 3501 ~ 4000
Heads 473 410 16 421
Tails 27 90 484 79

Test Log 2048-JP-2 – Date 2020/04/06

Conducted by: Dr. Mochizuki

Subject: SCP-2048-JP

Method: D-1872 is instructed to examine the properties of SCP-2048-JP in the same method as the previous test.

Result: The following results were obtained. Detailed test records are available in Appendix.

Analysis: It was confirmed that SCP-2048-JP-1 repeatedly decreases and increases. However, the cycle seems to become shorter as the accumulated number of trials grows.

Coin surface / Number of trials 1 ~ 400 401 ~ 800 801 ~ 1200 1201 ~ 1600
Heads 347 105 49 193
Tails 53 295 351 207

Subsequent test records are available in Appendix.

Since the containment, Dr. Mochizuki conducted 19,000 tests of SCP-2048-JP until 2020/04/29 (including tests at the time of Anomalous Item registration decision). Based on the results, he deduced the function of SCP-2048-JP-1 against the cumulative number of landing and characterized its properties. Trials prior to containment were ignored as they were not recorded and were not considered to make a significant difference. The following table and graph summarize the results of all the tests.


Graph 1: A graph representing the estimated value of SCP-2048-JP-1 against the cumulative number of trials for landing of SCP-2048-JP. It is not rendered accurately, due to the cycle shortening abruptly as the cumulative number of trials increases. The only statistically reliable values are the data before 10000 cumulative trials, as well as part of the data before 15000 trials; the rest are extrapolations based on those.

Range (cumulative number of landing) Properties of SCP-2048-JP-1
Overall It changes like oscillation; the cycle shortens rapidly in proportion to the cumulative number of landing.
After 10000 trials Since the change becomes extremely rapid, some intervals do not provide statistically sufficient samples for inference. Note that there is no method to determine SCP-2048-JP-1 at that time in such intervals.
After 15000 trials A sufficient number of samples cannot be obtained in any of the intervals.
After 18000 trials The rate of change becomes excessively large. As the error between the probability calculated from the inferred function and the actual SCP-2048-JP-1 is too large, the inferred function no longer has any significance. This also makes it impossible to observe periodic changes; the changes of SCP-2048-1 are considered to be practically random. See Addendum.

Addendum: Currently, SCP-2048-JP-1 is considered to change randomly due to the aforementioned properties. If SCP-2048-JP-1 changes randomly whenever SCP-2048-JP is flipped, and there is no way to know the probability that SCP-2048-JP-1 represents, the probability that SCP-2048-JP lands with its head-side facing up is practically 50% at all times. Assuming that SCP-2048-JP-1 changes in such a manner, this is an undeniably anomalous phenomenon, but no difference from a non-anomalous coin can be observed. This means that there is no scientific evidence that the anomalous properties of SCP-2048-JP-1 still exists. Based on this, a discussion is underway to determine whether the Object Class of SCP-2048-JP should be reclassified as Neutralized.

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