"Old Master Roshi has in his possession a very powerful fan made out of a palm-leaf called the Bansho Fan. It's the only thing that will extinguish Fire Mountain."
The Bansho Fan (芭蕉扇 Bashō-sen, lit. "Banana Palm Fan") is a mystical fan designed to stoke and control the flames of the magical furnace.
"What?! The Bashō-Sen?! The magic fan that can raise a typhoon with a single wave, a thunderstorm with two and a monsoon with three?! That Bashō-Sen?!"
The Bansho Fan is thought to have been created from the feathers of the Hikui Bird, although this may be untrue as Master Roshi admits it to be a guess (in the original Japanese version, Roshi states that he was drunk when he wrote the book containing "instructions" to make the fan). Master Roshi once used the fan as a potholder, but he threw it away after he spilled wonton soup on it. It has the power to control weather, and is described by Roshi as having the capability to "create a strong wind with a single wave, a cloud with two, and a downpour with three."
The fan was last seen in the possession of Goku in the last few episodes of Dragon Ball, when he once again needed it to extinguish the flames on Fire Mountain. Originally Goku and Chi-Chi attempted to construct a new fan by collecting the feathers of the Hikui Bird but they are unsuccessful, though a scientist studying the Hikui Bird reveals that a Bansho Fan can be found in a cave. While Chi-Chi stays with Grandma Hakkake, Goku goes in search of the cave, though only encounters the Pilaf Gang. Meanwhile, Chi-Chi discovers that Grandma Hakkake found the fan which she ends up finding in Hakkake's garden. It is this Bansho Fan that Goku uses in the last few episodes of Dragon Ball. Goku attempts to use the fan to put out the fire on Fire Mountain, but it fails. At Mount Five Element, Goku and Chi-Chi encounter Grandpa Gohan whom they briefly mistake as the keeper of the Furnace of Eight Divisions which is the source of the flames engulfing Fire Mountain, only to learn Grandpa Gohan is the Attendant of Annin, the goddess who guards the furnace which connects Earth and Other World. Goku tries to get Annin to put out the furnace, but she refuses noting that it would take a long time to relight it which would result in Earth being cut off from Other World. Goku is forced to fight Annin who transforms into her Giant Form, forcing Goku to use the fan against her only for her to stop fighting upon seeing the fan as it proves Goku's worthiness. she instructs him on how to patch up the hole in the furnace using the Bansho Fan and some of the honey they got from Grandma Hakkake. Ultimately, Goku is able to patch up the hole which causes the fire engulfing Fire Mountain to cease, allowing Goku and Chi-Chi to finally get married (additionally Goku & Chi-Chi's misadventures involving the fan allowed deceased Grandpa Gohan to meet Goku's fiancee).
Video game appearances
In Dragon Ball Z Side Story: True Plan to Eradicate the Saiyans - Earth Saga, Piccolo uses the Bansho Fan to quell a storm near a volcanic area.
It is the Z-Fighter Exhibit #4 in Dragon Ball Z: Buu's Fury, with its description being: "A mystical fan capable of creating an extremely strong wind. The original Bansho Fan was owned by Master Roshi, but was lost. Goku and Chi-Chi made a new one." It is trophy No. 47 in Dragon Ball: Advanced Adventure, and also a treasure that can be found in the first stage of Dragon Ball: Revenge of King Piccolo.
"A round fan. It raises a typhoon in one wave, a thunderstorm in two, and a monsoon in three."
— Dragon Ball Xenoverse Accessory description
In Dragon Ball Xenoverse, it appears as an accessory for the Future Warrior which can be purchased from the Accessory Shop after completing the Demon God Démigra Saga. However its function is purely cosmetic and it cannot be used as a weapon.
In Dragon Ball Legends, Adult Chichi from Dragon Ball wields the Bansho Fan which she uses to launch mini-typhoon or mini-typhoons in place of standard Ki Blast & Ki Blast Arts. Additionally Chichi (DBL09-06) utilizes the Bansho Fan as part of her Whirlwind Impact Ultimate Move Arts where she charges forward wielding the fan then spins around several times to generate a powerful typhoon which inflicts major damage on the opponent. It should be noted that during the Tournament of Time, Chichi (pre-23rd World Tournament) had managed to obtain (or construct) a Bansho Fan at some point before she meets Shallot and Caulifla.
- In "Dress in Flames", while in Octagon Village, Goku and Chi-Chi discover a giant rock with a map of how to make the fan. The instructions appear to be carved in the Namekian language, though it is a mystery what connection the Nameless Namekian or his fissions had with the Bansho Fan.
- Other than the fact it is used by Piccolo (after fusing with Kami and becoming the Nameless Namekian) in Dragon Ball: Plan to Eradicate the Saiyans. Presumably the restoration of the Nameless Namekian gave Piccolo the knowledge of the Bansho Fan construction or Piccolo was able to create one with Magic Materialization using the Nameless Namekian's knowledge of its construction and magical properties. Alternatively, if it was associated with Kami (who can speak the language, he could have informed Piccolo of how to make one). If it was associated with King Piccolo, then Piccolo would have inherited the knowledge from King Piccolo due to being his reincarnation.
- The Bansho Fan bears a great resemblance to a dansen uchiwa, a Japanese signalling fan also known as a gunbai or gunpai. This particular type of fan was made famous by Japanese warlord Takeda Shingen when he used his dansen uchiwa in a duel against Uesugi Kenshin during the Fourth Battle of Kawanakajima in 1561.
- The Bashōsen is based on a tool from the Chinese classic novel Journey to the West. In this story; there are two demon king brothers, known as the Great King Kinkaku (金角大王 Kinkaku-daiō) and the Great King Ginkaku (銀角大王 Ginkaku-daiō). The siblings possess five treasured tools, one of which is called the Banana Palm Fan (芭蕉扇 Bashō-sen). It is also based on the fan of , the character who Chi-Chi is based on.