Mystic Swordsman LV6
Attrib: Earth
Type: Warrior/Effect
Level:6
Atk: 2300
Def: 1700
If you Normal Summon this card, you must place it in face-down Defense Position. 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. You can return the monster destroyed with this effect to the top of your opponent's Deck instead of sending it to the Graveyard.

so just wondering if i special summon him not by the effect of lv 4 it stays face up stitll right?

If not by the effect of Mystic Swordsman lvl 4, you can Normal Summon Mystic Swordsman lvl 6 by tributing a monster from your side of the field and setting him face down for a turn. After a turn, if he survives being face down on the field, you may flip summon him on your following turn. At this time you may choose to attack your opponent.

The only time he is Set face-down Defense is if you are attempting to Normal Summon it...since there is no "Special Summon-only" text or Nomi Text anywhere, there is nothing stopping you from Special Summoning it except other card effects that would prevent you from doing so (like Jowgen the Spiritualist)

thank you all that is a big help