You can Tribute 1 Zombie-Type monster; Special Summon 1 Zombie-Type Tuner with 0 DEF from your Deck. If this card is banished: You can target 1 of your banished "Shiranui" monsters, except "Shiranui Solitaire", or up to 2 instead if "Shiranui Style Synthesis" is on the field; Special Summon them. You can only use each effect of "Shiranui Solitaire" once per turn.
Can only Special Summon 0 defense monsters from the deck.
The Shiranui archetypes main strategy is banishing their own monsters and triggering their effects, usually this is done by other Shiranui monsters as effect cost. Shiranui Solitaire is one of the best playmakers in the deck.
Since all Shiranui monsters have 0 defense, you can Special Summon any of them from your deck. The revival effect is good because Shiranui decks banish their monsters a lot. If you are able to revive 2 monsters, you can revive a Tuner and non-Tuner for Synchro plays.
You can use this field Spell to continually revive Shiranui Solitaire every turn so that Shiranui Solitaire can keep pulling monsters out of your deck. Aside from that it does give you an extra revive when Shiranui Solitaire is banished.
IIRC it's a joke about how Shiranui in TCG was once called as a solitaire deck due to doing a lot of things over a long period of time in one turn, almost as if the player is just playing by himself (hence "solitaire").