If you thought the only relationship between Tamil and Japanese is RajiniKanth, think again. Linguists are studying the relationship between these two great languages and to an extent successful in establishing the relationship between the two. In this article, Susumo ONHO compares the two languages in terms of phonetics, grammer correpondence, similar words etc., Though the article is pretty interesting, based on the evicence given, it is hard to decide whether there is any link between these two languages at all. Decide for yourself.
(Trivia: Japanese never had a written script till the 5th century. Now they have more than 3. Namely – Kanji, Hiragana, Katakana and Romaji – the last one uses Roman Alphabets)