Here is a medium and fine whetstone ideal for japanese steel knives. It also comes with a nagura stone which can maintain the whetstone by lapping (flattening) uneven areas.
This whetstone scored 4.5/5 stars on amazon from 91 reviews, though on the forums it apparently can dish (wear) quickly and will need to be sanded or lapped.
I purchased a Tojiro DP chef knife on the after dark ebay sale for $97 delivered- https://goo.gl/ysHsXS
This is reknowned as the best bang for your buck chef's knife under $100.
I was looking at how to maintain the edge and determined that whetstone/waterstones are the way to go for the hard japanse steel as honing steels tend to chip them.
1000 grit is for sharpening and 6000 grit will hone the edge
The cheapest avaiblable at the moment is $71 one ebay- https://goo.gl/JSsTKr
Unavaible here at everton (different model?) at $44.95- https://goo.gl/ssO2ul
Best value around under the shun equivalent for $90-$100 which is also low on stock on most sites in AUS
Can we use these on Global knives?