The Kojiki contains the myths of Japan's formation as a polity. It draws on both stories of heavenly deities as well as conquering heroes. Below are some websites that have either excerpts from or the whole text of the Kokiji.
Preface:
kojikipreface.html
http://www.wsu.edu:8080/~wldciv/world_civ_reader/world_civ_reader_1/kojiki.html
http://orias.berkeley.edu/japanlinks.html#Kojiki
http://j-myth.info/english/kojiki01.html
http://www.genji54.com/japanese%20classical%20lit/kojiki.htm
http://www.ninpo.org/historicalrecords/kojiki.htm
http://www.sacred-texts.com/shi/
Glossary:
http://www.kokugakuin.ac.jp/ijcc/wp/glossary/index.html