Johan, regrettably the diagrams in my previous posts are not very clear, they're OK if you know what you are looking for, but if you do not, they can be confusing.
The kanyut is the second last named part before the extreme end of the greneng, it is the part that looks like the decline of a hill, the last part is the buntut mimi, which viewed from above becomes the buntut urang.
There has been extensive discussion on tangguh over years in this forum. Different people think about it in different ways. The best way for a collector who is outside the heart of the keris world in Central Jawa to think about it is that the names are simply classifications. Names associated with old eras will refer to old keris, names associated with recent eras will refer to more recent keris, but it is best not to think of the name of the classification as always inferring an age for the keris. With younger keris, say, after mid-17th century, there can be a grain of accuracy in a link between name and era, but in older keris not a lot of people will accept that the tangguh name really links to the age of the keris, but it is likely that the name will link to a geographic location.
EDIT
This might be useful Johan:-
http://www.kerisattosanaji.com/keristangguh.html