on right click holding a gunpowder:
  name of held item contains "§a§lSkill §4§l[Bom]"
  lore of held item contains "§7Cooldown: §a5s"
  set {_cooldown} to difference between {skill.%player%.lastused} and now
  if {_cooldown} is less than 5 seconds:
    message "&cあなたは &a5秒間 &c待たなければいけない"
    stop
  else:
    execute console command "/effect %player% 11 1 255 true"
    create safe explosion of force 2 at player
    execute console command "/title %player% times 10 30 10"
    execute console command "/title %player% title {""text"":""\u00a7c\u00a7lスキル発動！""}"
    set {skill.%player%.lastused} to now

on right click holding a feather:
  name of held item contains "§a§lSkill §3§l[High]"
  lore of held item contains "§7Cooldown: §a10s"
  set {_cooldown} to difference between {skill.%player%.lastused} and now
  if {_cooldown} is less than 10 seconds:
    message "&cあなたは &a10秒間 &c待たなければいけない"
    stop
  else:
    execute console command "/execute %player% ~ ~ ~ /effect @e[name=!%player%,r=4] 25 3 5 true"
    execute console command "/title %player% times 10 30 10"
    execute console command "/title %player% title {""text"":""\u00a7c\u00a7lスキル発動！""}"
    set {skill.%player%.lastused} to now

on right click holding a iron_sword:
  name of held item contains "§a§lSkill §c§l[Kill]"
  lore of held item contains "§7Cooldown: §a50s"
  set {_cooldown} to difference between {skill.%player%.lastused} and now
  if {_cooldown} is less than 50 seconds:
    message "&cあなたは &a50秒間 &c待たなければいけない"
    stop
  else:
    execute console command "/execute %player% ~ ~ ~ /kill @e[name=!%player%,r=4]"
    execute console command "/title %player% times 10 30 10"
    execute console command "/title %player% title {""text"":""\u00a7c\u00a7lスキル発動！""}"
    set {skill.%player%.lastused} to now