Tsunade looked at the golden-haired young man before her, his sunny face still bearing a trace of childishness, yet undeniably handsome and dashing.
At this moment, it perfectly overlapped with the two most important figures in her memory: Senju Nawaki's vibrant smile and Kato Dan's unwavering gaze.
A sudden emotional impact made Tsunade's heart, locked away for many years, beat faster.
She suddenly stepped forward, extending her fair, slender arm. With her index finger bent and held by her thumb, she approached Naruto, seemingly about to flick his forehead.
"Hmm?"
"Are you going to flick my forehead—"
Naruto, somewhat puzzled, looked at Tsunade.
The next moment, Tsunade did not flick Naruto's forehead. Instead, she bent down and, without warning, kissed Naruto's forehead.
Tsunade lowered her head slightly, imprinting a soft, warm kiss on Naruto's smooth forehead—a kiss filled with immense gratitude, trust, and acknowledgment.
Time seemed to stand still at this moment.
Only the hazy white mist from the hot spring, Tsunade bending over, and the pendant dangling between her Great Snow Mountain, swaying and sparkling with intoxicating light, remained.
This was the precious pendant Jiraiya said could easily buy several mountains.
Tsunade, however, took off the pendant and placed it back around Naruto's neck.
"Naruto, this necklace belongs to you from now on. Protect it well."
Naruto's body stiffened. The faint scent of sake and the mature fragrance of a woman from Tsunade's body enveloped him, making him feel somewhat flustered.
Immediately after, Tsunade extended her finger and gently flicked Naruto's forehead, saying with a bright and cheerful demeanor, as if all gloom had been swept away:
"Thank you, Naruto."
Naruto raised his hand and touched his flicked forehead.
"That was careless. If it wasn't for Tsunade's kiss just now, which unsettled my heart, I could have dodged her forehead flick," Naruto thought to himself.
"Oh, and according to our agreement—"
Tsunade turned around, facing Shizune, who had just entered the hot spring, holding Tonton, and was stunned by witnessing Tsunade's kiss and the gift of the necklace.
"Shizune, pack our bags. It's time to return to the village. The Fifth Hokage of Konoha—"
"I, Tsunade, will take the position!"
Shizune nodded blankly.
Tonton, sleeping soundly in her arms, turned over, let out a comfortable grunt, and continued her nap.
"Sister Tsunade—"
Naruto suddenly called out to Tsunade.
He certainly wouldn't forget the true purpose of this trip.
"I want to learn the Yin Seal."
"Yin Seal…"
Tsunade pondered for a moment, then nodded:
"The Yin Seal was taught to me by my grandmother. It originally belonged to the Uzumaki Clan's sealing Ninjutsu, but I improved upon it."
"Alright, then I will teach you the Yin Seal!"
"But let me make it clear first, the Yin Seal, which I developed and perfected, is a genuine S-rank Ninjutsu, and it also includes the advanced Strength of a Hundred Seal and Creation Rebirth."
"By mastering the Yin Seal, you can achieve instant healing, enhanced attacks, and increased speed through subtle Chakra regulation."
"Skilled users can even achieve eternal youth, improved physical functions, and maintain their body in its prime state by low output and fine-tuning of Chakra within the Strength of a Hundred Seal."
Naruto smiled and nodded: "Don't worry, Sister Tsunade, I'll learn it very quickly."
"Is that so? Then watch carefully, Naruto."
Tsunade's voice was low and clear.
"The essence of the Yin Seal is the ultimate art of 'storage' and 'release.' It is not simply a Chakra container, but rather, highly refined life force, spiritual energy, and Chakra, compressed and stored within a special 'gate' on the forehead using a unique 'Yin' nature sealing Ninjutsu formula."
A point of glowing blue Chakra gathered at Tsunade's fingertip, gently touching the center of the diamond-shaped mark. The mark instantly lit up, emitting powerful energy fluctuations.
"In daily training, the refined Chakra, exceeding one's own load limit, is continuously poured into this 'gate' like a trickling stream, undergoing tempering, compression, and storage."
"This process requires extreme patience, precise Chakra control, and a deep understanding of one's own life energy flow."
From this, it is clear that practicing the Yin Seal is still very difficult.
It truly lives up to its S-rank medical sealing Ninjutsu status.
In the original work, only Sakura Haruno inherited Tsunade's Yin Seal; even Shizune failed to master it.
Naruto sat cross-legged opposite her, his azure eyes unblinking, observing Tsunade perform the Yin Seal through the apperceiving god's rune of wisdom.
As for the perception and precise control Tsunade mentioned, for him, that was even less of a problem.
Through the Transparent World, Naruto clearly "saw" the trajectory of Chakra flow within Tsunade's body and the precise and complex energy structure of the Yin Seal.
"The difficulty lies in the construction and maintenance of the 'gate'."
Tsunade continued: "This requires a special Chakra nature transformation, as well as the perception of energy imprints on the soul level."
"It's like an incredibly precise lock, and the key is your own will and Chakra characteristics. Even a slight deviation can result in storage failure, or in severe cases, damage to the soul's origin."
The Yin nature transformation of Chakra.
This, of course, did not stump Naruto, who had "perfected" Chakra nature transformation.
Tsunade looked at Naruto, her eyes complex, "Your Chakra reserves are incredibly vast, and the Nine-Tailed's power is even more volatile."
"To construct a 'Yin Seal' capable of containing your power would be far more difficult than for an ordinary person. But if you succeed—"
A glint of anticipation flashed in Tsunade's eyes, "Its power upon release would likely overturn the Ninja World's understanding of the 'Strength of a Hundred Seal'."
"I understand—"
Naruto pondered for a moment, withdrew his gaze, closed his eyes slightly, his expression serene.
His powerful mental energy and Chakra perception instantly converged, and he began to attempt to construct that precise "gate" on his forehead according to the secret method taught by Tsunade.
Tsunade looked at his focused expression, feeling the vast yet precisely controlled Chakra within his body, and was filled with emotion.
"This young man truly has infinite potential. Is it because the Nine-Tailed is sealed within him? I actually see my grandfather's shadow in him."
"Shizune, let's go."
"The Yin Seal isn't that easy to master. Let's go back first and pack our luggage."
"Yes, Lady Tsunade."
Shizune was about to follow Tsunade, but suddenly noticed Tsunade stopping, abruptly turning around, and looking at Naruto, who was sitting cross-legged on the hot spring, with a look of surprise and uncertainty.
Naruto's brow line was outlined by an even more perfect diamond-shaped pattern.
And its pattern was golden!
It was different from Tsunade's Yin Seal pattern.
"This… this is the sign of mastering the Yin Seal!"
"Naruto—you?"
"Have you completed the Yin Seal cultivation?!"
Tsunade's voice trembled, filled with shock, doubt, and disbelief.
Shizune was even more dumbfounded.
As Tsunade's disciple, Tsunade had also taught her the Yin Seal, but she struggled to master it and eventually had to give up, pursuing the path of poison in addition to medical Ninjutsu.
But no matter what, no one understood the difficulty of cultivating the Yin Seal better than her.