Tuners

[Fever]

If you have the proper Synchro material Monsters on the field for a Synchro Summon, can you Synchro Summon a Monster using a Tuner that is Face Down?

[PkMn Trainer]

I believe both the Tuner and the Synchro Material have to be face up to conduct a Synchro Summon.

[Fever]

I believe both the Tuner and the Synchro Material have to be face up to conduct a Synchro Summon.

Yeah, from the replies I got on the other forums that sounds correct. Sucks. I am trying to make The Shallow Grave useful. I think it might be good in Dark World.

[Dragon in the Shadows]

I am trying to make The Shallow Grave useful.

Shallow Grave is awesome in a rock deck...Not that great in a deck that uses lots of Syncros.  Anywho I believe the Tuner and other monsters have to be face-up.

[Fever]

Yes, now I know the Monsters have to be face up to Synchro Summon.  

[Yami-Karasu]

Although the initial question has been answered, something else came up in here...
What would it take to make The Shallow Grave to work in a Dark World Deck? Basically, there are two usable Flip effect monsters: Morphing Jar and Night Assailant. In case The Shallow Grave would be used to revive either one of them, your opponent would be aware of it. Well, nuking the field would be more or less their only option to stop them though. So little players have any other way of stooping a face -down monster. DAD counts as nuking in my opinion.
Night Assailant would more or less just destroy the monster your opponent summoned... Then again, you could always use Dark World Lightning yourself. This would bring the card a target, which would be perfect. The combo wold be easy to use and effective. You'd only need 3 cards in your hand, one of which ought to be a Dark World monster, preferably Sillva or Goldd.
Aside from the two mentioned monsters, there are few monsters with which this card could be useful. In vase you run a synchro deck, a Dark Resonator could work out. No Dark World monster would be worth summoning at the very least. Renge is ridiculously bad in a DW Deck although he could work in something else. Scarr would worth considering... But I'd never run him myself.

[Fever]

Well you pretty much said it all lol.