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Kogetsu Optional Trigger: Senkū. A momentary lenghtening of the blade's reach through a trion expenditure. The swinging blade is most deadly at the tip.

Senkū's description, in Large-Scale Invasion 3.[1]

Senkū ((せん)(くう) lit. Rotation Void?) is an Optional Trigger exclusive to Kogetsu,[1] including its spear variant.[2] An attack carried out using this Trigger takes the name of Senkū Kogetsu ((せん)(くう)()(げつ)?).[1]


Senkū has no physical manifestation outside of its effect on Kogetsu, whose blade it extends. Due to the speed of the swing, the attack can appear only as a ribbon of light originating from the blade.[3] Should Kogetsu be a different color than the standard one, the blade will be changed back to its default color.[4]


The origins of this Trigger are unknown. Due to its function, it cannot have been created before Kogetsu.


Senkū allows the user to temporarily extend their Kogetsu's blade by consuming trion for vastly increased reach[5] and cutting power[1]. The power of the slash peaks at the tip of the blade.[1] The extension is inversely proportional to the duration of the effect.[6] the majority of Attackers keep it activate for 1 second, resulting in a range of 15 meters, but Tatsuhito Ikoma can comfortably execute a Senkū Kogetsu slash with the activation time being a mere 0.2 seconds, which causes the blade to extend up to 40 meters.[7] This extreme application of Senkū can cut cleanly through large Escudo barriers,[8] but even an ordinary activation has proven capable of cleaving through a minimum of five smaller Escudo, some within a few meters of the Senkū user, without difficulty.[9] Kei Tachikawa used this Trigger to bisect two Rabbits vertically[10] despite the very durable armor on their head and back being capable of resisting two simultaneous Scorpion slashes without taking any significant damage.[11]

Shinoda's focused Senkū Kogetsu.

Skilled Senkū users like Ikoma[12] and Tachikawa[3] are able to swing the elongated Kogetsu twice within one same activation, while Yōsuke Yoneya was able to strike five times in a row with his Spear,[2] although it is possible that he simply extended the activation time. Another notable application of Senkū is the one demonstrated by Masafumi Shinoda, consisting in pinpoint attacks which resemble Mantis more closely than a proper slash.[13] He also displayed the ability to avoid obstacles,[14] although whether he did so through sheer skill, in conjunction with Gen'yō, or through a customization is currently unknown.

Shinoda,[15][14] Tachikawa[16] and Ikoma[17][18][18][19] are consistently shown sheathing their Kogetsu between attacks, and the act of drawing it has been repeatedly recognized as a telling sign of the wielder's intention for activating Senkū[20][21] — although there are also instances of it being unequivocally activated when Kogetsu was already out of the scabbard.[3][4][22] However, whether the act of sheathing and drawing Kogetsu has any use remains unconfirmed. The speed at which Kogetsu extends and shrinks is likewise unknown.

Senkū must be equipped on the same side of the slots as Kogetsu in one's Trigger set, and can thus be activated even if two Triggers are already in use.[23]


Name Description
Tachikawa and Murakami attack Gatlin.gif Double Senkū Kogetsu
(ダブル(せん)(くう)()(げつ) Daburu Senkū Kogetsu?)[23]
The user activates Senkū through both the Main and the Sub while wielding two Kogetsu.[23] This technique was very likely used by Kei Tachikawa to effortlessly cut down an Ilgar,[24] whose already durable armor was enhanced as it was ready to self-destruct.[25]
Ikoma Senkū
(()駒旋空(こませんくう)(こま) (せん)(くう) Ikoma Senkū?)[26]
By activating Senkū for a mere 0.2 seconds, the user can extend the reach of their Kogetsu up to 40 meters. This complex technique, which requires the user to swing their sword extremely quickly while synchronizing the slash with the activation of Senkū, is named after Tatsuhito Ikoma, the only person in Border capable of using it.[7]


See also: Senkū Users

There are 27 known users of this Trigger among official agents,[27][28] including Yōsuke Yoneya, who activates it through his Spear.[2] Masafumi Shinoda also has Senkū in his Trigger Set.[29] Tatsuhito Ikoma is hailed as the best Senkū user in all of Border,[30] but Shinoda and Kei Tachikawa are also worthy of note.


  • The way Kogetsu is often unsheathed right before using Senkū is probably a reference to Battōjutsu, where one draws their sword from the sheath only moments before striking.
    • Similarly, Ikoma was taught Iaido and has always sheathed his Kogetsu when doing his special Senkū, so it is possible that anyone who uses it has to learn Iaido to pull it off correctly.
  • In the English translation of Chapter 154, Yuu Kunichika heavily implies that Senkū can be activated only while drawing Kogetsu; however, the original text makes no mention of it.[7]
    • Viz might have made that assumption in the translation process. It is possible she was talking about Ikoma's Iaido Stance.
  • Kyōsuke Karasuma, Shūji Miwa and Kotarō Tomoe are the only three official agents that have Kogetsu but not Senkū in their Trigger set.[31][32][33]


  1. 1.0 1.1 1.2 1.3 1.4 1.5 World Trigger Manga Chapter 57 (p. 11)
  2. 2.0 2.1 2.2 World Trigger Manga Chapter 131 (p. 4)
  3. 3.0 3.1 3.2 World Trigger Manga Chapter 26 (p. 6-7)
  4. 4.0 4.1 World Trigger Manga Chapter 172 (p. 12)
  5. World Trigger Manga Chapter 26 (p. 6)
  6. World Trigger Manga Chapter 154 (p. 4)
  7. 7.0 7.1 7.2 World Trigger Manga Chapter 154 (p. 5)
  8. World Trigger Manga Chapter 188 (p. 19)
  9. World Trigger Manga Chapter 172 (p. 2-3)
  10. World Trigger Manga Chapter 57 (p. 12-13)
  11. World Trigger Manga Chapter 46 (p. 15-16)
  12. World Trigger Manga Chapter 157 (p. 2)
  13. World Trigger Manga Chapter 71 (p. 4-5)
  14. 14.0 14.1 World Trigger Manga Chapter 71 (p. 8)
  15. World Trigger Manga Chapter 70 (p. 17)
  16. World Trigger Manga Chapter 132 (p. 9-10)
  17. World Trigger Manga Chapter 154 (p. 1)
  18. 18.0 18.1 World Trigger Manga Chapter 158 (p. 6)
  19. World Trigger Manga Chapter 188 (p. 16)
  20. World Trigger Manga Chapter 132 (p. 11)
  21. World Trigger Manga Chapter 154 (p. 8)
  22. World Trigger Manga Chapter 172 (p. 19-21)
  23. 23.0 23.1 23.2 Daisuke Ashihara: Q. 167: Does ‘exclusive options’ not count in the only two triggers at a time limit? They don’t. Exclusive options, like Kogetsu’s exclusive ‘Senkuu’, are equipped on the same side of the slots as Kogetsu, and only switched ON when in use (the trion consumed is only what the exclusive option used). Dual-wielding Kogetsu + (Senkuu x 2) for a ‘Double Senkuu Kogetsu’ is also possible. It is implied that switching Triggers is not as fast and/or as practical as activating a Trigger when the column (Main or Sub) is not already in use.
    Source: Border Briefing File, Page 307, Question 167
  24. World Trigger Manga Chapter 48 (p. 5)
  25. World Trigger Manga Chapter 48 (p. 9)
  26. World Trigger Manga Chapter 153 (p. 19)
  27. World Trigger MangaBorder Briefing File
  28. World Trigger Manga Chapter 161 (p. 16)
  29. World Trigger Manga Chapter 70 (p. 16)
  30. World Trigger Manga Chapter 150 (p. 10)
  31. World Trigger MangaBorder Briefing File (p. 95)
  32. World Trigger MangaBorder Briefing File (p. 79)
  33. World Trigger MangaBorder Briefing File (p. 181)


Border Triggers
Basic Equipment Bail OutRadarTrion Body
Attacker Kogetsu (Kogetsu: Spear) • Raygust (Shield Mode) • ScorpionSōgetsu (Axe)
Gunner AsteroidCobraGimletHornetHoundMeteorSalamanderTomahawkViper
Firearms Assault Rifle • Grenade Launcher • Handgun • Minigun • Shotgun
Sniper EgretIbisLightning
Defense EscudoShield (Fixed Mode/Full Guard)
Trap Switchbox
Optional BagwormBagworm TagChameleonConnectorDummy BeaconEnhanced RadarFull ArmsGeistGen'yōGrasshopperIdatenLead BulletMakōSenkūSilencerSpiderStarmakerTeleporterThrusterTimer
Prototypes ConnectorDummy BeaconFull ArmsGeistIdatenMakōTeleporterTimer
Black FūjinTsukihiko Amō's Black TriggerYūma's Black Trigger