Diary

Biodata

Appearance

The Diary has a pure black cover with gilded lettering identifying Naruto as its writer and naming the copy’s holder 1. Other copies look almost identical 3.

• A holder can make her copy vanish and reappear at will 2.
• Tsunade cannot damage her copy, even when she tries to tear it apart 3.

History

Naruto begins writing after awakening memories of another world. Worried that village surveillance will expose him, he accepts the system’s assurance that observers will not notice anything unusual about his writing or discover his Diary. Sakura nevertheless receives a separate copy and reads his first entry 1.

Copies subsequently appear before women including Hinata, Yugao, Tsunade, and Shizune. Their readers learn that they can discuss the Diary with fellow holders, though attempts to disclose it to outsiders provoke a warning of danger. Tsunade and Shizune discover the friend feature when their copies touch 2 3 4.

Naruto later suspects that others can read his entries. By watching Tayuya’s reaction after calling her “my dear wife” in an entry, he concludes that this wording can give a woman access to a copy 89 100 183. He deliberately uses the Diary to bring Hanabi into the circle of readers 369.

Abilities & Functions

Shared entries and foreknowledge

• Holders see Naruto’s entries as he writes them; their copies display the same contents 2 5 370.
• His accounts of the shinobi world’s history and possible future give readers information they can act on. Yugao, for example, reports Mizuki’s suspicious behavior after reading Naruto’s expectations for the graduation period 8.
• Entries also expose Naruto’s private judgments and relationships, sometimes embarrassing or angering their subjects 18 87 164.

Rewards

• Completing entries grants Naruto system rewards. His first is the Perfect Sage Body; later rewards include techniques and increases to his abilities 2 7 18 369.
• Holders mentioned repeatedly can receive rewards too. Hinata, Ino, and Sakura each gain doubled chakra and physical abilities; Yugao later receives the same reward 5 11.
• Rewards can significantly change a holder’s condition: Yakumo’s doubled chakra and physical fitness leave her dramatically healthier 158 159.

Private communication

• Holders can add one another as friends and communicate through their Diaries instantly, regardless of distance 4 8.
• A Group Chat lets multiple holders speak together in real time 162 370.
• Holders may discuss the Diary with one another, but its rules forbid revealing the Diary itself to outsiders. Information learned from an entry can be shared without disclosing its source 3 32 214.

Notable Holders

• Sakura Haruno — finds the first shown reader’s copy 1.
• Hinata Hyuga and Ino Yamanaka — receive copies and form a private connection with Sakura 2 3 8.
• Tsunade and Shizune — compare their copies and discover long-distance messaging 3 4.
• Uzuki Yugao — receives a copy while bathing and uses its information to investigate Naruto 3.
• Kurama Yakumo — initially mistakes her copy for a hallucination before Kurenai confirms it is real 154 155.
• Ōtsutsuki Kaguya — reads a copy while sealed within the moon 22 23.
• Hanabi Hyuga — receives a copy after Naruto deliberately addresses her affectionately in an entry 369.