Complex sentence: The a-side track was used as the commercial song for Playstation 2's "Sengoku BASARA 2", while the b-side song was used as the theme song for MO-N! "Harmony with the Earth ID".
Split into simpler sentences: The a-side track was used as the commercial song for Playstation 2's "Sengoku BASARA 2". The b-side song was also used as the theme song for MO-N! "Harmony with the Earth ID".