From my past life, I know for an absolute fact that April 1st, 2015, fell on a Wednesday.
Let's track it forward. Since 2016 is a leap year, April 1st of 2016 shifts two days ahead. Wednesday plus two days lands on Friday.
Okay, so April 1st, 2016, is a Friday. Now, I just need to count backward to find the day for March 8th.
March has exactly thirty-one days. If April 1st is Friday, then March 31st is Thursday. March 30th is Wednesday. March 29th is Tuesday.
Exactly three weeks prior to March 29th is March 8th. Since a week is exactly seven days, the day of the week remains identical.
That means March 8th, 2016, falls on a Tuesday.
I tap my finger against the mattress.
Tuesday. Not Monday.
Ayanokouji explicitly stated that March 8th was a Monday. The math proves that in 2016, it is a Tuesday. The calendar is off by an entire day. Therefore, the opening line of the novel is a huge contradiction. Year 2015 is debunked.
Just to be absolutely certain, I move to the second piece of evidence. The fatal blow comes from Chapter 4 of Year 2, Volume 2.
Chabashira-sensei stands at the podium and delivers the rules for the upcoming island exam. Her dialogue is incredibly precise. She tells the class: "...from today until the end of Friday, July 16..."
This occurs during their second year. The month is July.
This confirms that July 16th of the second year is a Friday.
If the first year started in 2015, then their second year takes place in 2016. That means Chabashira-sensei is referring to July 16th, 2016. Let's run the calculation again. I already established that April 1st, 2016, is a Friday. I just need to count the days forward to July 16th.
April has thirty days. Subtract the first day, leaving twenty-nine days in the month. May has thirty-one days. June has thirty days. And we need sixteen days in July.
Twenty-nine plus thirty-one is sixty. Plus thirty is ninety. Plus sixteen is one hundred and six days.
Divide one hundred and six by seven. Seven goes into one hundred and six fifteen times, which equals one hundred and five. That leaves a remainder of exactly one day.
So, July 16th is exactly fifteen weeks and one day after April 1st.
If April 1st is a Friday, shifting forward by one single day lands on Saturday.
July 16th, 2016, is a Saturday.
Chabashira-sensei clearly called it a Friday. The math shatters the dialogue. Year 2015 is officially dead and buried.
I shift my weight, sitting up a bit straighter against the headboard.
Based on the hard data extracted from the text, I need a calendar timeline where March 8th is a Monday, and July 16th is a Friday.
Do those two dates even align in a normal year? I run the numbers in my head. March 8th to July 16th is exactly one hundred and thirty days. Divide by seven, and you get eighteen weeks and four days. If March is a Monday, adding four days gives Tuesday, Wednesday, Thursday, Friday.
Yes. It aligns perfectly. The internal calendar of the universe is highly consistent with itself. It just doesn't match the year 2015.
So, what real-world calendar years actually possess a Monday, March 8th?
I cycle through the leap year patterns in my mind. The matching calendar years for this specific alignment are 1999, 2010, 2021, and 2032.
These years perfectly match the two data points. Since these dates officially occur during the second year of high school in the story, I have to go one year backward to identify the very first day of school. April 1st of Year 1.
So, the four candidates we have to be the present year in this universe are 1998, 2009, 2020, and 2031.