The sealed letter, dated July 1984, asked whoever found the bottle to return it to the school, Choshi High School. The message in the bottle, titled “Survey of Ocean Currents,” was written by students and placed in the Kuroshio Stream near Miyajima Island in western Japan as part of a school project on ocean currents, CNN writes. The Institute said it released 450 bottles in 1984 and another 300 in 1985 as part of the experiment. So far 51 have been found and returned. However, the school added, this is the first bottle found since 2002.