There should be other ways to obtain the Field notes.

[Mahamon]

Hopefully they add this in as part of Patch 5.58, let us spend coins to buy the missing notes we need. I've got a heap of Bozja coins I'm not using, let me spend them on something lol.

At this point, even 999 coins sound way more appealing than praying before opening the chest. (ﾉ*･ω･)ﾉ At least, we can work on grinding and there's an end in sight.