1. Using the Western number system:
* 一九九七 (pronounced "ichi-kyuu-kyuu-nana")
This is the most common way to write 1997 in Japanese, using the kanji characters for each digit.
2. Using the Japanese counting system:
* 千九百九十七 (pronounced "sen-kyuu-hyaku-kyuu-juu-nana")
This method uses kanji for each place value (thousand, hundred, ten, etc.).
Both methods are correct and understood, although the Western number system is more commonly used for dates.