Bankai Byakuya compared to Shikai Ichigo.[]
Byakuya in his Bankai state can react to Ichigo in his Shikai state Byakuya's Senbon Zakura Kageyoshi is faster than Ichigo, as Ichigo is suprised how fast it is and how quickly it could defend Byakuya and then appear behind him to strike him .
∴ Bankai Byakuya's Speed => Shikai Ichigo's Speed.
Bankai Byakuya's Speed[]
To calculate the multplier of Tensa Zangetsu we don't need a specific speed, we can use any arbitrary Speed for Byakuya, for this calculation we would use mach 1. This means Byakuya has a combat speed of mach 1 or 343 m/s and a reaction speed of 0.00291545189 second.
Note - We can also say that Byakuya has combat speed of x and reaction speed of 1/x, the speed we assumed does not matter at all.
Tensa Zangetsu's Multiplier[]
Calc[]
After Ichigo transforms into his Bankai, the distance between Ichigo and Byakuya is 8.555... meters.
According to Byakuya himself he lost sight of Ichigoand he couldn't even reaction.
Speed = Distance/Time.
The Time here being the reaction speed of Byakuya which is the time it takes for him to react to something moving, Ichigo had to move to Byakuya before he could react so the Time should be below 0.00291545189 second.
The Distance here is the distance between Ichigo and Byakuya and the distance Ichigo travelled which is 8.555... meters.
∴ Speed = 8.555.../0.00291545189.
Bankai Ichigo's Speed = 2934.555... m/s or Mach 8.555... or 8.555... times faster than Bankai Byakuya.
If Bankai Ichigo is 8.555... times faster than Bankai Byakuya and Bankai Byakuya's speed is around Shikai Ichigo's Speed if not greater, then Ichigo's Bankai multiplies his Speed more than 8.555... times on top of his Shikai.
Conclusion - Ichigo's Bankai Speed multiplier = 8.555...+ x Speed of Shikai Ichigo.
Does this align with the series ?[]
• As Yoruchi states in Chapter 120, the difference between Bankai and Shikai interms of combat ability is 5 to 10 times.
• Byakuya states, Tensa Zangetsu's ability is to fight at super high speed.
• In Bleach: Official Character Book SOULs it states, "It (Tensa Zangetsu) channels all of the bankai power into speed, thus allowing the user (Ichigo) to battle at a feverish pace."
• Grimmjow goes as far as to say the only thing Ichigo's Bankai does is give him average speed.
So Tensa Zangetsu's combat ability is to increase speed, therefore the speed difference between Zangetsu and Tensa Zangetsu should be about 5-10 times.
Conclusion - Ichigo's Bankai Speed multiplier is between 5-10 times or 8.555...+ x Speed of Shikai Ichigo to be precise.