The Soul Torch (人魂灯 hitodama-tou, "Hitodama Torch") is a palm-sized paper lantern which attracts phantoms when lit, used by Yuyuko Saigyouji (and her servant Youmu Konpaku) as part of her duties in the Netherworld. Yuyuko can light or extinguish the Torch from any distance, and Rinnosuke Morichika suspects that she can sense its current location as well.
Youmu loses the Soul Torch some time prior to chapter 10 of Curiosities of Lotus Asia, after which it is found by Rinnosuke Morichika at Muenzuka and brought back to his shop. In chapter 13 Yuyuko discovers this and activates the Torch remotely, causing Kourindou to become overrun by phantoms and allowing Youmu to track down and retrieve it.
In Touhou Hisoutensoku, the Soul Torch appears as a System Card which summons phantoms to attack the opponent.
In Impossible Spell Card one of the items stolen by Seija Kijin is the "Ghastly Send-Off Lantern" (亡霊の送り提灯), which makes the player temporarily invincible. Whether this was intended to be the same item as the Soul Torch is unclear.