The clue is not misleading. "Ichi" means "one" and "ichiban" means "number one." It depends on the context, but usually "first" would be "daiichi," as in "anzen daiichi" (safety first).
For "V" I kept trying to figure out how to spell "Gundam" or "Go Lion" or "Doraemon" with a "V". I realize "Go Lion" doesn't start with a V, but could you accept the answer since they are the same show?
oh.... should have remembered Ichiban from that old movie we watched in film class where the ugly American kept going around asking very loudly to speak with the "Ichiban! Number one guy!"
I kept typing Voltes V, which was older than Voltron. It was dubbed in English on its first showing in my country, where it was popular. Maybe consider it as an alternate answer? It was also dubbed in English for the North America release in 1983.
There is a Sushi place called Ichiban near my house and I was killing myself trying to remember the name and couldn't. I almost broke and just yelped it...arrrrgh.
The question "Former name of T" baffled me, I understand what it means now but I thought T might be an actual thing rather than a reference to another question. Maybe it could be rephrased as "Former name of current capital city"?
"Arigato" or "Arigato Gozaimasu (respectfully)" is for thanks. Domo Arigato is different as it is a sentence meaning "thank you very much", which you would not normally say, unless it was for something major. So you got it wrong. It's like telling everyone "Sayonara", when you will only be gone for a few hours, it would make you look stupid.
I also tried "Valkyrie" (Macross).
I didn't know Voltron, maybe I'll check it out...