The Kayou Naruto North America program uses 23 rarity tiers, from base R / SR / SSR commons up through the serialized chase cards. Every card's number encodes its set, rarity, slot, and L-tier (pull difficulty L1–L5).
Rarity tiers include R, SR, SSR, HR, PTR, PU, UR, MR, BP, SP, AR, SE, CR, and the diamond-stamped ◇UR, ASP, and ◇ASP chases. NRSA02 introduced AR; NRSA03 stacked ◇ASP / ◇UR / HR / ASP; NREA01 brought the CR cloud tier; NRCCNA (Ninja Age) adds QR (Embroidered), XR (Illustrated Scroll), and diamond parallels ◇QR /72, ◇XR /9 + /99, ◇MR /999, plus the first ◇PR (Diamond Promo).
A card number like NRSA02-UR-001L3 reads as a sentence: NRSA02 is the set, UR the rarity, 001 the slot, and L3 the L-tier. Each rarity ships at its own fixed L-tier.