Ichigo Kurosaki vs. Ikkaku Madarame

Ichigo Kurosaki vs. Ikkaku Madarame was the first fight between a seated member of the Gotei 13 3rd Seat Ikkaku Madarame of the 11th Division and intruder Ichigo Kurosaki. within Seireitei at the beginning of the Ryoka Invasion. The battle though between two combatants did considerable damage to the street on which it took place, with both combatants sustaining injury until Ikkaku falls unconscious out from severe injuries.

Also notable that though trained in a short amount of time Ichigo is able to keep up with Ikkaku who has at least a centuries worth of training. Ikkaku himself also makes note that in many ways Ichigo's skills in swordsmanship rivals his own.

Battle
Ikkaku and Yumichika Ayasegawa are the first Shinigami to encounter Ichigo Kurosaki and Ganju Shiba upon their intrusion into the Seireitei. Ikkaku does his Tsuki-Tsuki dance to give Ikkaku and Ganju time to exit their sand pit and becomes irate when they just stand there looking at him. Ichigo and Ganju get into an argument about possibly fighting which prompts Ganju to run off, while Yumichika chases after him, Ikkaku is left to fight Ichigo. After resolving why Ichigo didn't run off as well Ikkaku attacks but Ichigo dodges and attacks but Ikkaku blocks him with his scabbard. Ichigo breaks free and attacks from above as Ikkaku attacks from below resulting in small cuts near both their eyes, they then exchange names. Ichigo wipes the blood from his brow, to which Ikakku states that he doesn't understand as only a rookie would remove both hands from his sword. Ichigo explains that the blood is getting in his eyes and Ikkaku chides him telling him that he should find some way of stopping the bleeding so he wont have to do that, as he applies ointment in a small compartment in the hilt of his sword to his brow stopping the bleeding of his own wound. Ichigo calls him a cheater but Ikkaku states that in fact he is just smart. He tells Ichigo is weird to him as his actions are that of a rookie so he cant really tell that he is a warrior. But he notes that his reactions are very fast and his attacks are very strong, while his body movements are close to his own. Still unsure of what to make of him, Ikkaku asks Ichigo who is his teacher. Ichigo explains that he only taught him for ten days so he doesn't know if that a true teacher but his name is Kisuke Urahara. Ikkaku's becomes somewhat surprised and states that if he is Ichigo's teacher then it would be very rude of him to kill him so easily. Ikkaku then releases his shikai, much to Ichigo's surprise and rushes at him. Ikkaku strikes at Ichigo to which he dodges and blocks the attack, only to be followed by a flurry of attacks. Ichigo thinks he has the upper hand stating that it takes longer to attack with a spear, but Ikkaku warns him that he is wrong as he swings at Ichigos head before it is blocked. Ikkaku then surprises Ichigo as he says a second release command causing his shikai to split into a three-sectioned staff causing Ichigo to react before the spear head can hit him square the face, blocking with his forearm causing it a deep wound. Ikkaku then tells Ichigo that Hozukimaru isn't a spear but a Sansetsuken. Ikkaku details that Ichigo wont probably be able to use the arm to wield his sword any longer and is surprised with Ichigo uses the cloth at the end of his hilt to wrap his arm and then attack. Ikkaku moves just in time as Ichigo destroys the wall behind him with a single downward slash. Ichigo states that it seemed like Ikkaku finished talking but he doesn't know Ichigo's sword and the next time he will be the one who wont be able to hold his weapon. Ikkaku goes on the offensive once again and attacks, the continue to battle with Ikkaku gaining the upper hand until Ichigo notes that he is getting use to fighting against his weapon. Ikkaku is noticeably surprised that Ichigo was able to to stop his Hozukimaru single-handedly. Ichigo then goes on the offensive and cuts Ikkaku's Hozukimaru in half, while dealing a deep wound to the center of his chest as well. Ikkaku laughs and tells Ichigo he should give up as he can still hold his sword, to which he takes the bladed end and spins it as he advances. Ichigo yells at him to put it away as he has already lost but Ikkaku refuses stating that the only way he will lay down his weapon is if he is dead and he will never walk away from a fight like a coward. The two collide resulting in Hozukimaru breaking further as a grievous wound is dealt to Ikkaku's arm. He notes that Ichigo was too strong as he falls to the ground unconscious.

Aftermath
Ichigo's defeat at Ikkaku's hands gained him a semblance of respect from Ikkaku. It also allowed Ikkaku's captain Kenpachi Zaraki to gain some small intelligence on what he would be up against when the two finally crossed paths. This fight set the tone for the destabilization of a normally organized society as the Shinigami scrambled to stop the intruders at all costs with little to no intelligence as to what the threat they faced really was.