Travelling to Japan with kids

I've been having this crave lately for traveling to Japan and I'm debating whether to go next year... However, if I do so, I will be traveling with my 3 kids who will be 6 years, 4 years and 10 month old... I spent quite a lot of time in Japan back in 2012 when I was studying there so my goal is not to do extensive sightseeing but maybe visito Osaka and Tokyo (maybe some day trip if justifies) and take things slowly while doing some stuff that might be cool for the kids (Universal Studios, Disney, Pokemon stores, etc.) during 2 weeks... However, I feel I might be pushing my luck in traveling to Japan with such young kids... Any experiences you can share?

It's doable, but from experience I can tell you it will take you a lot longer to get from place to place, plus in Japan there is a lot of walking - so if you are climbing a lot of stairs or hiking up a hill, your kids might give up somewhere along the way.
Some family restaurants are also a good way to satisfy picky appetites - they have a lot of familiar foods and variety. Hopefully you can also try some really Japanese places too though.

I travelled to Japan with a 5yo, 3yo and 11mo when I first travelled to Japan. So near similar ages.

I would recommend it. Such young ages are high needs. I would wait as long as you can before travelling internationally.

While quite do-able to travel. I found we were concentrating on baby stuff more than I wanted to, consider I was there for Japan.

I went again 3 years later, ages 8, 6 and 4. And it was so much easier. No nappies, no day sleeps. Eldest could carry and pull a small suitcase.

Typo
I wouldn't recommend it.