[lucagalbu]

Hi all!
I can't figure out what "dan dan" means in the japanese opening of dragon ball gt by Field of View. it's written in katakana so it should be a foreign word, but of what language?

Also this phrase: "kimi to deatta toki" what does toki stands for? Why is it written in hiragana and not whit kanji? And if the translation was "when i met you", shouldn't it be "kimi ni deatta toki"?