The Japanese written language is considered one of the most complex in the world because it uses two different syllabaries of 48 characters each called hiragana and katakana and 2000 some ideographs borrowed from China. The chart below shows the similarity of Hebrew characters to that of Japanese script.
I am of course very familiar with both katakana and hiragana. Katagana is used to write the sounds of most non-Chinese loan words in Japanese, and hiragana is used for verb endings and for Japanese words that would need a Chinese ideograph that is hardly ever used. The Japanese script shown in the chart is mostly katakana but also shows 4 hiragana characters that are even more similar to a Hebrew character than its katakana counter-part character is.
I’ve never studied Hebrew and don’t know Hebrew characters. However from the chart, it seems pretty convincing to me that Japanese syllabary scripts are based on Hebrew script, and therefore would mean the ancient children of Israel did in fact come to Japan in the early part of the first millennium!