Han-Kon-Ko/Notes

{| border="0" cellpadding="1" cellspacing="1" class="article-table" style="width: 660px;"

Origin
Han-Kon-ko, or Hangonko, is a legendary incense known for summoning a dead soul. The Incense plays a major role in this ceremony. Though, this doesn't actually happen, it was very popular back then. Going through this ritual does no harm.

Other
This is actually very similar to the youkai, Enenra, which is a youkai made of smoke.