Yaiba finally subduing Raijin's influence and taking full control of the Raijin Katana.
Yaiba:" I...I...I am...... Yaiba Kurogane!"
During the first serious clash against Onimaru, Yaiba imbues his Kaminari Giri (Lighting Slash) with Raijin's power, resulting in a huge Lighting wave that break the Fujin Sword and splits Onimaru's castle in half!.
The whole part of the Ryujin's Trials is a huge CMoA for everyone. Expecially Jubei against the hordes of mummies in the second trial, Musashi finding out the solution of the third trial, the Seacucumberman bringing the Torch of Life back to them and Sayaka performing an Heroic Sacrifice to allow Yaiba to proceed.
Onimaru's army got one: when faced by Kaguya in a huge all-out battle he and his servants manage to hold on for 24 Hours before biting the dust. Not mentioning Onimaru's Tornado-Drilling Kaguya throught Mount Fuji!.
Yaiba and Onimaru join their powers to defeat Gekko's Devil King Sword. The result is Freaking Awesome.
Yaiba flying to space with Ryujin's powers and Blasting Kaguya with a Earth-Shattering Kaboom inducing attack and sealing her for good..
Also Yaiba's victories over Jewel and Demon-Gold with the Supreme King Sword.
Kojiro got one against Silver: the behemoth was busy crushing him into a pulp with his right hand and all Yaiba's attempts of freeing him were unsuccessful. He managed to free himself by making his magical sword growing and piercing that blasted cyclop in the eye!
The final Battle between Yaiba and Onimaru on the Orochi's Body..
The Oda Nobunaga Tournament arc had several, including the battles against Gozuma, Jubei, Soshi Okita and, of course, the big, great Final Battle with Onimaru inside the burning Honnoji temple.
The battle against Okita deserves credit: Basically, Yaiba managed to triumph even if Okita was effortlessy beating him up with his matchless swordstyle, and not because of his strength or skill, but because of his pure, sheer stubborn spirit.