What does the "503 day" refer to? In multiple fanarts and fanfic websites of Full Metal Alchemist, I have seen mentions of the "503 day". Here's an example:



I did read and watch Full Metal Alchemist and Full Metal Alchemist Brotherhood and I do not remember any mention of such a date. It does not match with the date Ed engraved into his State Alchemist Pocket Watch either.

What does the "503 day" refer to?
503 day is supposed to be the 3rd of May (5/03), which is the Edward x Winry day, or Edwin day in short.

There are two reasons for this coming into existence.

First, there's a jeans brand called Edwin and one of their logos contains the number 503.



Second, when Winry goes to Central City she's in room 503 of the hotel.