This first movement is a gyaku yokomen uchi.
For the exercise, one often and by purpose strikes the attacker's weapon. Don't be mistaken.
In reality this would be meaningless in Aikido: all strikes with no exception, whether in aikijo or aikiken, aim at the opponent's body.
Don't mistake the necessities of the study with the demands of reality.
In Aikido one does not protect himself, one does not block or parry, one does not evade, one does not fight against a staff or a sword, in Aikido one does irimi.
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.