Cheapest priced copy (Kamigawa: Neon Dynasty): $0.35 at Card Kingdom, near mint, their price list as of .
Heiko Yamazaki, the General 
Legendary Creature — Human Samurai · 3/3 · Uncommon · Kamigawa: Neon Dynasty · #146
Trample
Whenever a Samurai or Warrior you control attacks alone, you may cast target artifact card from your graveyard this turn.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Kamigawa: Neon Dynasty | 146 | Uncommon | $0.35 | $0.49 |
| Kamigawa: Neon Dynasty | 321 | Uncommon | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 18 February 2022A creature attacks alone if it's the only creature declared as an attacker during the declare attackers step. For example, Heiko Yamazaki's triggered ability won't trigger if you attack with multiple creatures and all but one of them are removed from combat.
- 18 February 2022You must still pay all costs and follow all normal timing rules when casting an artifact from your graveyard this way. Normally, this means you will not be able to cast that card until your post-combat main phase.