Before deciding which knife (Continental or Japanese) you should consider your style of cutting as well.
Continental knive are made of thick hard steel 55-57 hrc and hold edge at around 20* angle.
They are durable, don’t chip as easy and are relatively easy to sharpen up.
Japanese knive use even harder and thinner steel at 60-63 hrc and hold edge from 17*-13* angle.
VG10 steel is relatively maintenance free, no need to worry when puting it into dishwasher etc. At 60hrc its good enough to cut thin tomato slices as well as crushing bones without fear of breaking blade.
If you were knife afficionado you could venture into damascus carbon steel blades 62+hrc and those extreme 13* angle edge, but those are more boutique and require some maintenance and care after every wash.
To own japanese knife, one needs to learn to work/sharpen with wetstone to get most out of exquisite blades. So Continental knive are easier to live with in that respect (handle knife sharpeners are handy and easy to use).
There is no such a thing of knife staying sharp for ever, but Japs do hold their edge better.
As chef’s knife I personally wouldn’t go shorter than 21cm but would couple it with 12cm pairing knife. You also need to consider your kitchen size before opting for 27cm blades, they are extremely Pro and usefull but man, you’ve got to be serious to use them (chopping zombies in half more like).
So here you are, HTH and the reason Tojiro DP were recommended for VFM.
http://nipponkitchen.com/acatalog/Tojiro_DP_Range.html
and review
http://www.knifeforums.com/forums/showtopic.php?tid/856342/