Why did Tesco bother with Japan?

Tesco finally found a buyer for their Tesco, Tesco Express and Tsurukamerando chains in Japan, but the question has to be why they ever bothered in the first place. Reading about the whole story of their unsuccessful stint in Nippon, I think is must be because there has (much to my surprise) never been a truly national chain of supermarkets in Japan and Tesco thought they could be the first.

The ironic thing is that in all kinds of ways they have helped Aeon approach that position. Apparently after Tesco bought up Tsurukamerando, Aeon offered any other chain that needed buying up more money than Tesco would offer them. They also copied and improved on the Tesco Express concept with their My Basket chain, and in the irony of ironies Aeon is the buyer of all those Tesco scores (after Tesco pays to have them all rebranded as Aeon!)