Well, all I can say is that the harvesting rules probably alter
according to climate. And planting time. I have harvested garlic in
mid winter -waaay after the tops died down, they're mushy then if
it's been wet although a few do survive to regrow next year. I've dug
them up in summer too, but they weren't ready. I don't understand
your 5 leaves left bit. Mine never get more than five anyway. When
they
*start* to go yellow, they have obviously stopped growing. I do
reccommend a dry day though, easier to dry them off.

NZ climate is temperate. So quite how Osaka's would be different I
can't say. But a google search found plenty of advice :-)

It is obviously a matter of research. How is your Portuguse? The
abstract is English but the article isn't.
http://www.scielo.br/scielo.php?scri...rm=iso&tlng=en

More temperate info.
http://www.tropical-seeds.com/tech_f...=en&ie=U TF-8

Try a search on garlic tropical and harvesting. See what you find.

--
Cheers,
Loki [ Brevity is the soul of wit. W.Shakespeare ]