When did the Japanese start using kanji?

It's a bit tricky to say definitively when the Japanese "started using" kanji, as it's been a gradual process with several stages. Here's a breakdown of the key developments:

* 5th-6th centuries AD: This is when the earliest known examples of kanji being used in Japan appear, on artifacts like the "Haji Tombstone" and the "Kudara Kannon" statue. These were likely borrowed from the Chinese, who had been using kanji for centuries.

* 7th-8th centuries AD: During this period, kanji was heavily adopted for official documents and religious texts. The Taika Reforms (645 AD) encouraged the use of Chinese-style writing, and the spread of Buddhism brought with it a need for translating Buddhist scriptures.

* 8th-10th centuries AD: The "Manyogana" system emerged, using kanji to represent Japanese sounds, similar to how we might use English letters to represent sounds in a foreign language. This was a key step in developing a writing system specifically for Japanese.

* 10th-12th centuries AD: The "hiragana" and "katakana" syllabaries gradually developed from simplified forms of Manyogana. These provided a more efficient way to write Japanese, alongside kanji.

So, while the first kanji appeared in the 5th-6th centuries, it wasn't until the 7th-8th centuries that it became widely adopted and the basis of Japanese writing began to evolve.

It's also important to note that the use of kanji continues to evolve today. New characters are created and adopted, and the usage and simplification of existing characters change over time.