Heart Of Clear Water+Mystic Swordsman Lv2+Tsukuyomi

Mystic Swordsman Lv2
Effect Monster
If this card attacks a face-down Defense Position monster, destroy the monster immediately with this card's effect without flipping it face-up or applying damage calculation. During the End Phase of a turn that this card destroyed a monster as a result of battle, by sending this card to the Graveyard, Special Summon 1 "Mystic Swordsman LV4" from your hand or Deck.

Heart Of Clear Water
Equipment Spell
If the equipped monster's ATK is 1300 or higher, this card is destroyed. The monster equipped with this card is not destroyed as a result of battle or by the effect of a card that targets the monster. (Damage calculation is applied normally.)

Tsukuyomi
Effect Monster, Spirit
This card cannot be Special Summoned. This card returns to the owner's hand during the End Phase of the turn that it is Normal Summoned or flipped face-up. When this card is Normal Summoned or flipped face-up, select 1 face-up monster on the field and flip it into face-down Defense Position.

This has to be one of my favorite and evil combos to use, but to my surprise, not many people use it, even though many are familiar with it.

The process of this combo goes like so:

Summon Mystic Swordsman Lv2 on the field, and equip the equipment spell card Heart Of Clear Water to it. then finish your turn. Next turn, if your opponent has a face up monster on the field, summon Tsukuyomi to flip it face down and attack it with Mystic Swordsman Lv2, and attack with Tsukuyomi (Make sure your opponent can’t destroy Tsukyomi with a trap, or else you’re in trouble). If you already had a monster on the field, you should end your opponent pretty quickly.

Some other cards that you might want to use with this combo is Magic Jammer, Magic Drain, Royal Decree, Solemn Judgement, cards that prevent your opponent form destroying your key cards.

So come one, try it out.

Of course, with every good there is a bad.

With Heart of Clear Water protecting MS Lv2 from death, it's basically a pinata out there getting smacked around all the time. Meanwhile, you have to you your only normal summon to summon a Tsukuyomi that will only net you the only satisfaction of destroying the monster while face-down.

Great combo, but I can see why it's not used too often.

also, you need to protect Mystic from non-targeting monster effects. Smashing Ground will destroy this plan pretty quickly.

Unless they have another monster...in which case...chances of Mystic Swordsman LV2 being hit by it is slim to none.

Anyways...yeah, the combo isn't really that great (and it's old except replace MS LV2 with Sasuke Samurai). Not to mention there's still more cards that can stop it over cards that you can stop them that I'm sure you would want to smush into a Deck.