We have 6 nights to spend in this area. In order not to pack/unpack many times my idea was to be hotel based in Osaka doing day trips to Kyoto and Nara.
Any idea of the chepest way for travelling 2 adults and 2 children aged 11 and 5 between Osaka-Kyoto and Osaka-Nara, by train or bus or rental car ?

I would base myself in Kyoto. Driving is not cheap or easy in Japan even if you speak the language. Nav systems may make it easier to drive but cost will not be cheap. Bus is probably the cheapest way of getting around but the train is the easiest and quickest in most cases.

Bonjour Fabio,

Unless you really have to stay in Osaka, you'd be better off staying in Kyoto, and doing day(s) trip(s) to Osaka and Nara, given the ratio of interesting things to do and see in the 3 cities.

Inside Kyoto, take Yen 500/day bus cards (IIRC, your 5 yrs old should not pay and your 11 yrs old gets a discount). You can also rent bicycles (ask at tourism office - hotel desk - look at www.kyotoguide.com). Nara is 45 min away by train (JR or Kintetsu - Nara Kintetsu station is closer to the deer park and great Buddah than JR) and costs around Y 600 for an adult. To Osaka, JR has frequent trains (around 550/adult) that take around 30 min.

I would definitely base your self in Kyoto and take a day trip to nara from there. Kyoto in itself is worth 10 days and you still won't see everything. If you only have 6 days don't waste it in Osaka.

thank you

you are right but we are in a rush extremely last minute request, we leave in 5 days, monday 2nd, and almost everything looks sold out in Kyoto due to the cherry-blossom season, unless for unaffordable rates !
That's why I was considering Osaka.
However I have now found 2 nights in Kyoto inbetween the 6 nights and am trying to extend the whole stay in the same property or somewhere else in Kyoto.
Osaka is the "spare" solution !! After all it is only 35 minutes by train from Osaka...