"So, now the training begins!" Kakashi propped himself up with his crutches and looked over his students.

"Yes, sir!" Naruto grinned enthusiastically.

"But, before that..." Kakashi held up a finger. "Let me explain again Chakra power for a Ninja, from the beginning."

"At this point...?" Sasuke closed his eyes for a moment and put a hand in his pocket.

"Of course we know about that!" Naruto nodded. "Chattora, right?"

"It's Chakra..." Kakashi corrected, letting out a heavy sigh as he shook his head slowly.

Naruto chuckled nervously. "H-Heh..."

Kakashi glanced to Sakura. "Yes, Sakura?"

Sakura cleared her throat quietly and put her hands on her hips. "Are you listening, Naruto?! It's tiresome, so I'll explain it simply!" She held up a scroll for him to see, then rolled it so he could see the writing and illustrations. "Chakra is energy that a Ninja requires when he uses a Jutsu!"

"It's made up of two energies." Sakura pointed to the images. "One— Physical energy gathered together from each and every cell in the body and, two— spiritual energy accumulated based on training and experience!" Sakura looked at Naruto to be sure he listened, then looked down to the scroll. "In other words, Jutsu wrings out and combines those two energies from within the body and this is called 'combining the Chakra.' Then, Chakra is activated by forming hand signs."

"That's exactly right!" Kakashi smiled at Sakura, then looked at Sasuke and Naruto. "Iruka really does have good students."

"Hee." Sakura giggled to herself and smiled at the praise.

"Whatever!" Naruto complained. "I may not understand difficult explanations, but I'll just learn it with my body!"

"Naruto's right." Sasuke spoke up and looked at him from the corner of his eye. "We're already able to use Jutsu..."

"No! All of you still haven't used Chakra efficiently."

"What?!" Naruto glared at him.

"Hold on and just listen..." Kakashi continued. "As Sakura explained earlier, combining Chakra means picking up both the physical and spiritual energies and mixing them together within the body. And of course, the amount of each energy and the preparation of the energy changes based on the Jutsu you want to activate. Thus, all of you at present aren't using Chakra efficiently!"

Kakashi paused and his eyes rested on Naruto. "Even if you're able to combine a lot of Chakra, if you're not able to control it in a balanced way, the effectiveness of the Jutsu not only will be cut in half, but it may not even activate at all. Wasting energy like that will prevent you from battling for long periods. These are some of the weaknesses that can occur."

Naruto blinked slowly and scratched the back of his head. "So... What should we do?"

"You need to learn to control the Chakra with your body!" Kakashi narrowed his eyes seriously. "It's difficult training that requires you to put your life on the line to master!"

Sakura gulped slightly. "W-What will we be doing?"

"Hm?" Kakashi held up a finger. "Tree climbing."

"Tree climbing?!" The three asked simultaneously, incredulous.

"That's right!" Kakashi nodded. "But it's not just simple tree climbing! You'll climb without using your hands."

"What?" Sakura's eye twitched. "H-How?!"

Kakashi noticed their expressions and sighed slightly. "Well! Just watch."

Kakashi formed a hand sign and focused Chakra to his feet, then used the crutches to walk himself to the nearest tree, placed his foot on the trunk, and began to walk up.

Their eyes widened and Naruto's mouth gaped open. "He's climbing..."

"...Perpendicular to the tree and with his feet!" Sakura finished his thought, staring in amazement.

"So... see?" Kakashi walked on the underside of a branch, hanging upside down, and looked at them. "Kind of like this... Focus the Chakra on the bottoms of your feet and make them stick to the tree trunk. If you use Chakra well, you can do things like this easily."

"Wait a minute!" Sakura looked up at the Jonin. "How does something like that make you strong?"

"So, this is the main point..." Kakashi explained. "The aim of this training is to accumulate the required amount of combined Chakra to the required spot... This is something difficult even for expert Ninja. The amount of Chakra used for tree climbing is very subtle, and the bottoms of the feet are the most difficult place to gather Chakra." Kakashi glanced at his feet, then to his students. "Anyway! In other words, if you master that control, it will be possible to master any Jutsu. In theory, that is!"

"The second aim is to maintain that combined Chakra." Kakashi went on. "Ninja combine the most Chkra during battles. Under such situations, control and maintenance of Chakra becomes most difficult. So... anyway, nothing's really gonna happen with me saying this and that... You'll need to learn it with your own bodies."

He threw three Kunai down, and one landed in front of each of them.

"Use those Kunai to put a mark at the spot where you can climb up to under your own strength now. Next, make an effort to put a mark further from it. You aren't good enough to walk up from the start, so run and use your momentum to get used to it... You got it?"

"This training is nothing!" Naruto reached down to retrieve the Kunai with a slight smirk. "Ha! This is too easy for me!" He grinned up at Kakashi. "After all, I'm the man who's grown the most!"

"Enough with the talk..." Kakashi sighed. "Now get to it. Try climbing any tree."

Naruto made a face and shut his eyes. Forming a hand sign, he focused intently. "Okay, so first I need to gather the Chakra on the bottoms of my feet..."

Sasuke and Sakura took the same pose and focused on their own Chakra.

Naruto opened his eyes with a smile and looked at a tree. "Ready! Here I go!"

He ran at the tree as Sakura and Sasuke did the same with their own trees. Naruto placed one foot on the tree and barely made it up another step before he fell to the ground and hit his head.

Sasuke ran steadily up the tree until the bark beneath his foot cracked. He marked the spot on the tree then leapt down, looking up to see how far he'd managed to get.

"I didn't think it'd be this difficult to maintain a constant amount of Chakra..." Sasuke gritted his teeth at the mark on the tree. "If the Chakra is too strong you get pushed back..." He turned to look at Naruto, who rolled on the ground, clutching his head as a bruise began to form. "But if the Chakra is too weak, there's no sticking power and... that happens."

Kakashi watched them from above. "Well, the difference between Naruto and Sasuke seems about right..."

"This is pretty easy!" Sakura giggled from a high branch and all eyes turned to her.

Naruto's eyes widened as he looked up at her. "S-Sakura!"

She giggled again and stuck her tongue at him.

"So, it looks like the one with the best control of Chakra is Sakura, the girl..." Kakashi looked at her.

"Wow! Way to go, Sakura!" Naruto beamed up at her. "Just what you'd expect from the girl I've set my sights on!" Naruto's smiled wavered momentarily. "But it does sort of tick me off!"

"Hmph." Sasuke looked away from her. "Whatever."

Sakura's expression fell as Sasuke's attention turned away. "I wanted Sasuke to notice me... why does this always happen?!"

"Not only does Sakura have knowledge about Chakra, but her control and stamina are also pretty good. It looks like... she might be the closest one to becoming a Hokage... unlike someone else." Kakashi chuckled slightly and Naruto scrunched his face, Kakashi chuckled again and looked at Sasuke. "And also... the famed Uchiha clan isn't really that great..."

"Shut up, sensei!" Sakura glared and pointed at Kakashi, blushing deeply. "Sasuke won't like me if you keep talking like that!"

"Ah, and... you know..." Kakashi looked back at Naruto, shrugging slightly. "I've heard that Natsumi already mastered this technique a while ago. It seems like you two have been surpassed by two girls..." He chuckled to himself. "How embarrassing for you..."

Naruto and Sasuke gritted their teeth and locked onto each other's eyes.

"Having said that... Naruto and Sasuke... those two have an incredible amount of Chakra hidden in them, that even Sakura can't match." Kakashi observed them from above. "If this training goes well, this will become an asset to them..."

"Okay!" Naruto smirked slightly and balled his hands into fists. "First, I'll catch up to Sasuke! I'll do it for sure!"

Sasuke turned away from Naruto and narrowed his eyes at his mark on the tree.

From behind a tree, Inari peered out to quietly spy on them. Aftersome time, he scoffed under his breath, turning away to leave. "Whatever..."

The boy glanced back at the Ninja momentarily before turning back around and continuing on his way. "Even if they do that, it's just a waste..."

Deep in the forests, in the fortress of assassins and mercenaries, Zabuza lay resting in a large bed as his apprentice sat beside the bed in silence.

The door opened hastily and the boy turned to look at the intruders.

"Unbelievable..." The short man looked at Zabuza and laughed to himself. "Even you got beaten and had to come back? The Ninja from the Hidden Mist Village look like total weaklings! You can't even clean up after your subordinates, and you think you're a "demon!" Don't make me laugh!"

Zabuza and the boy remained quiet and did not look at the man or acknowledge his presence. After a moment, the boy stood and Gato's guards reached for their swords in preparation as the magnate smirked.

"So... they're drawing swords..." The boy looked at the group through his peripherals.

"Hold on. Wait." Gato chuckled and stepped forward towards the bedridden assassin. "Hey! There's no need to stay silent! Why don't you say something?"

Gato reached out to grab at Zabuza's mask and the boy grabbed his arm tightly, holding him in place with a glare.

"Don't touch Zabuza with your filthy hands!"

Gato let out a scream as the boy's grip tightened. "I-It's gonna break!"

The guards reached to draw their swords and the boy looked to them, clenching his jaw, and flickered between the two, taking control of their swords and pressing their blades against their owner's throats.

The tattooed guard's eyes widened and he glanced sideways at the boy. "N-No way..."

The other guard froze in place and gulped. "He moved in an instant..."

"I wouldn't do that if I were you..." The boy warned with his eyes enlarged and wild. "...I'm ticked off!"

Gato turned and stared at the boy, speechless as he threw the swords to the ground behind him.

"Next time!" Gato shouted at Zabuza, retreating back to his guard's sides with a snarl. "If you lose again next time... remember that there will be no place for you here!"

The man pulled at the bottom on his suit jacket and adjusted his tie briefly before he turned and to leave. "Let's go!"

His guards followed closely behind and, once they had left, the boy approached the bed once more and Zabuza glanced at him.

"Haku... such unnecessary actions..." Zabuza clutched at a Kunai knife in his hand, hidden beneath the covers.

"I know." The boy lowered his head in apology and sat back down. "But it's too early to take down Gato right now... If we make trouble here... we'll be pursued by them again. Thus, we must restrain ourselves for now."

Haku smiled gently and rested his hands in his lap as Zabuza's gaze returned to the ceiling.

"Yeah..." Zabuza closed his eyes. "You're right."

"Aaaaah!" Naruto ran up the tree with his face scrunched in concentration, then slipped and fell once more onto his head. "Ow!" He rubbed his head and frowned as his fingers brushed the bruises.

Sasuke huffed as he recovered his breath, kneeling on the ground. He looked up at his tree and the cluster of marks there.

Sakura panted as she lay down under her tree, out of breath and covered in scrapes. "I'm totally worn out!" She looked over at the two boys and sighed under her breath. "How much stamina can those two have?"

Naruto rubbed his head, wincing in pain as he glared up at his markings.

"But Naruto isn't getting any better at all." Sakura giggled to herself. "He'll soon give up and start throwing a tantrum."

Naruto stood, still staring at the markings on his tree in frustration. "Shoot!"

"See!" Sakura sat up and watched him. "He sure is an easy one to figure out!"

Naruto walked slowly over to Sakura and she blinked. "Huh?"

"Hey, Sakura." Naruto squatted in front of her, then held up a hand to whisper. "Can you give me some tips?"

"What?" She blinked again at him.

"Let's keep it a secret from Sasuke!" Naruto pleaded in a hushed voice. "Come on, come on!"

Sasuke glanced over at Naruto, narrowing his eyes slightly as he whispered to Sakura and Kakashi watched Naruto. "He's getting stronger and stronger... How strong will he get? At any rate, Naruto, the amount of your dormant Chakra is probably more than Sasuke's. And it's even more than mine! I look forward to seeing you grow... I really do."