The author didn't provide information about when this book came out, nor is there any information to find on it. But I think at the book's release, Shift-JIS (t

The author didn't provide information about when this book came out, nor is there any information to find on it. But I think at the book's release, Shift-JIS (the standard) didn't exist yet. Rather JIS X 0201 ( https://en.m.wikipedia.org.org/wiki/JIS_X_0201 https://en.m.wikipedia.org.org/wiki/JIS_X_0201 ) was used, on which Shift-JIS is based.