Use this card to reset the effect of a Flip Effect Monster or a monster like "Snowman Eater" etc.
Like all Spirit monsters, use this card with "Creature Swap" to take one of your opponents' monsters, only to have this card returned to your hand at the end of the turn.
Use this card to abuse the weaker DEF of higher Level monsters, such as "Dark Armed Dragon" and "Caius the Shadow Monarch". Once these monsters have been flipped face-down, they can easily be destroyed by battle by this card.
This card can also destroy problematic high-ATK Level 4 and lower monsters in the same fashion, including "Thunder King Rai-Oh".
This card can be used in "Wind-Up" Decks, to reuse the effects of "Wind-Up" monsters.
Flip up "Mask of Darkness", and return "Time Seal" to your hand. Then set "Time Seal" and continuously do this in a loop (using this card to reset "Mask of Darkness") to prevent your opponent from drawing any new cards.
You can use this card in an Empty JarMill Deck to reuse the effects of key cards such as "Morphing Jar" and "Needle Worm". With "Book of Taiyou" in hand, you can mill an extra five cards from an opponent's deck and still have this card in your refreshed hand by the End Phase.