Silver Medal 5 Earned 5 or more silver medals.
Please see here for a brief explanation on medals.
Solution for メダル初獲得 In Bullet Soul (JP)You have to earn 5 silver (or better) medals to unlock this achievement. It's cumulative and both medals earned in normal mode or Banchou mode counts.
I don't think there's a merit in a solution for how to earn silver medal particularly, so just putting a link to the solution for the easiest platinum medal.
If you are trying for platinum, you'll have a good chance of earning silver or gold when you narrowly failed to get the platinum.
Related achievements (earned your first medal)
(5 gold medals earned)
(5 platinum medals earned)
(platinum on Banchou stage 1)
(platinum on Banchou stage 2)
(platinum on Banchou stage 3)
(platinum on Banchou stage 4)
(platinum on Banchou stage 5)
(platinum on all 5 Banchou stages)
(NOTE: Translations of achievement name or text in this guide are not official and might be wrong.)