It is much easier to aquire it in Chapter 3 instead of later. The only way you can get it is to beat Shinra in Sphere Break. You can do it in Chapter 3 when his quote is like 50 and you have an echo coin, or you can do it in Chapter 5 when his quota is like 200. You might have better coins in Chapter 5, but it's a little funny to see Shinra lose, especially since he was being so arrogant about winning. A very easy way to beat Shinra in the tournament is to just get three coins every turn. If you don't get a 1 ever, you can win in 12 turns.