Courtesan Monsters CAN be Normal Summoned, but they can be also
Courtesan Summoned. Courtesan Monsters MUST be Courtesan Summoned in order to activate their Courtesan Effect. (If you Special Summon them to the field, their Courtesan Effect won't activate, except by another effect...) You may recall that
Flip Monsters have "FLIP:" in their descriptions that tell you that they'll activate their
Flip effect if Flip Summoned. Likewise, Courtesans have "COURTESAN:" which tells you what Courtesan Effect will activate if they are Courtesan Summoned. Keep in mind, some Courtesans can have a regular effect, a flip effect, and/or a Courtesan Effect at the same time.
OK, so, how do you Courtesan Summon? Courtesan Monsters are Courtesan Summoned by the process called
Solicitation (LOL!). Solicitation is banishing (or removing from play, if you like that term) cards (Spell, Trap, and/or Monster) from your hand. Banished cards used as "tribute" for Solicitation are called
Gratuity or
Gratuities (LOL, paying gratuity for a courtesan's "service")! Gratuity is sort of like the Courtesan version of Tribute, Fusion Material, Xyz Material, or monsters used for a Ritual Summon.
Think of it like this, Fusion Monsters use Fusion Materials for "Polymerization" to be Fusion Summoned; well, Courtesan Monsters use Gratuities for Solicitation to be Courtesan Summoned, LOL! I don't know if that helped.....
Anyways, how many cards must be banished in order to Courtesan Summon? The normal Avalancher rule is:
Take the Courtesan's Level and divide it by 2. That's how many Gratuities (cards in your hand to be banished) are required for the Courtesan Summon. Round to the nearest whole number.
For example, "
Postal Schoolgirl" is Level 4. How many Gratuities (cards in your hand to be banished) would it take to Courtesan Summon that monster? Take her level (4) and divide it by 2. Therefore, you have to banish 2 cards to Courtesan Summon "
Postal Schoolgirl"! Yep, if you had a Level 12 Courtesan, you need 7 cards in your hand (the Courtesan AND the other 6 Gratuities for Solicitation), which goes beyond the
standard hand size limit.
Yep, theoretically, Courtesans' levels would have to be even-numbered. However, some card effects like
A Legendary Ocean could make a Courtesan's level odd-numbered. In that case, round up, LOL! So, if you had a Level 7 Courtesan, divide 7 by 2. You would banish 3.5 cards in your hand; of course, you can't banish 3.5 cards; so, round 3.5 to the nearest whole number, which is 4. So, for a Level 7 Courtesan, you have to banish 4 cards in your hand...
Some Courtesans require certain types of Gratuity. For example, "
Anemone Cyborg Kari" requires at least one card with "Kari" in it's card name. Other Courtesans may require 1 or more Gratuities of a certain card type (Spell, Trap, Monster) or a certain monster type (Machine, Sea Serpent, Fiend-Slut, etc...). As a rule of thumb, the harder it is to Courtesan Summon, the better the Courtesan Effect...