A couple of questions about Reasoning:
1. Can you activate it if you have 5 monsters on the field?
2. What happens if you activate Reasoning while you have 3 free monster zones and the opponent chains Ojama Trio?
Answer:
1) You cannot activate "Reasoning" in this situation.
2) Because "Ojama Trio" resolves first and fills up your available Monster Zone Spaces, leaving you with no available Monster Zone Spaces, "Reasoning" has no open space for the monster it will intend to Special Summon.
However, the effect of "Reasoning" is still applied. So you will still reveal cards from the top of your Deck until you reveal a monster that can be Normal Summoned. When you reveal a monster that can be Normal Summon, it will be placed into the Graveyard with the other revealed cards, because it was not possible for you to Special Summon it.
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Curtis Schultz
UDE Netrep
CurtisSchultz_Netrep@hotmail.com