Q. Can I survive in Japan without knowing any Japanese writing?
A. Unless you care about reading Japanese newspapers or novels, you will be fine. You do not need to know Japanese writing to speak, and as for speaking Japanese, pronunciations is not as difficult as you think. (There are only five vowels in Japanese.)
You can also use Romaji. With Romaji you can write Japanese without knowing Japanese writing. Many Japanese can read Romaji, though the Japanese do not use it to write, unless they are writing for foreigners.
If you want to write or read in Japanese, start learning hiragana and katakana. They are simpler than kanji, and have only 46 characters each. It is possible to write an entire Japanese sentences in hiragana. Japanese children start to read and write in hiragana before making an attempt to learn some of the two thousand kanji commonly used.
Vol. 27: How many kanji do I need to learn to read Japanese?