
When nikyo is executed on katate, kata or muna grab, grabbing uke's wrist with your second hand is possible (and necessary). There are many other ways to apply nikyo but this is the basic form, the kihon one must know and be able to identify.

But sode dori prevents you form grabbing uke's wrist with the and of your grabbed arm (your forearm's length does not allow it).
In that case, you need to "grab with your elbow ie: bring your elbow on uke's wrist with a rotating movement which goes from lower outside to upper inside.

When coming down, your elbow will fulfill the function your hand can't assume in that situation.

Uke's face is straight at atemi distance.
Aikido is not a sport, it is a martial art which laws (takemusu) are in harmony with the laws of the universe. Studying them allows the practitioner to understand his place in the universe. Aikido was born in Iwama, O sensei achieved in that village the synthesis of tai jutsu, aiki ken and aiki jo.
The International Takemusu Aikido Federation (ITAF) brings to the practitioner the structure he needs in order to work as close as possible to the reality O sensei MU defined. The official national representations are the guarantee of a teaching faithful to the Founder's.
In modern Aikido, weapons are hardly taught, if taught at all. In O sensei's Aikido, on the contrary, aiki ken, aiki jo and tai jutsu are unified and form together a riai, a family of harmonious techniques stemming from one unique principle. Each techniques helps understand all the others.
Peace is a balance between a human being and the world around him. The true martial art's goal is not to become stronger than one's opponent but to find in that opponent a way to realize harmony. There is no enemy anymore as such, but an opportunity offered to reach unified ki.