Any ideas how to achieve this colour?

I think pravana silver might be your best choice.

Nirvel Artx Nutra Colour in grey is much darker than Pravana Silver, more of a charcoal grey.

Thanks for the suggestions. I'm not sure if the Pravana silver would cover my hair, it's pretty dark in places. I haven't heard of the Nivel Artx product before, Wicked Pixie, have you used it before? Has it got a good pigment that covers well?

Nirvel is very dark and could be diluted a bit to get the color.  Joico titanium should give you that color straight out of the tube.

I use the Nirvel ArtX grey all the time.  I love the ashy effect, and yes, you can dilute it or use it more saturated depending upon the effect you want to achieve.

I was a very golden blonde, toning with Pravana Silver and other silvering products, then I tried a good saturation of the Nirvel grey, and I loved the effect.

Recently, I've been using it nearly undiluted to achieve a more gradated ombré, and though I first used a light brown permanent colour at the roots a couple weeks ago, this past weekend I covered it and blended it more with the Nirvel, just on the underlayers and top... this is how it looked after this weekend's colouring:

(I also did a colour remover at the ends, that's why it looks more golden toward the bottom.  It's still a work in progress. :))

Alexia, it's looks great! Thanks for the picture and Baby 3 thank you for the advice, I'll see if I can get my hands on it somewhere in Japan.

Have you looked into these, I have not used them but the results on the image look very similar http://item.rakuten.co.jp/starrich/cb/ 😀

Wow, they look great! I haven't seen these anywhere in stores in Japan. It looks like they have a really dark grey too, thanks so much 🙂