Follow directions for the standing stone, but when you reach the information board by an opening into the forest, enter here, this is the footpath marked on OS maps. Idwal couldn't find it, A Portaleer needed local help, but it's really not hard to find at all. It can be seen perfectly well on Google earth, in the corner of where the trees have been felled in an angled kind of way. Any way, follow the path through the dark forest, untill you come acoss some moss covered walls, pass through them making for the edge of the trees and the big white rock will shine at you through the trees. Simples.
Finding it was a simple matter when compared to interpreting it, it isn't apparently on Coflein, So i'm unsure of it's date. The information board has it incorporated into an archaeological walk, so there is some hope of it being old. It's proximity to the standing stone Cerrig y Cledd, the stone of the sword and to Cerrig Arthur stone circle, Arthur being well known for having a sword of some repute, both lend weight to it.
Ive added this site as a carving but it could equally have been a rocky outcrop, rock art, or engraved stone, it's probably best just to describe it.
The rocks look to have been one large rock at some time, two big chunks have broken off the main rock. One of the broken off rocks has a carved sword on it, where it has broken off the main rock is another carved sword shape, looking for all the world as if the rock broke open and a sword was revealed, Arthurian like. I would really like this to have been ancient, but it all seems too fantastic, perhaps it is an ancient carving, but I doubt that it was used in casting a sword or the finding of some miracle weapon.
Having said that it really should be sought out when visiting the menhir, I was elated and giddy for finding such a potential wonder of a site, my son thought me slightly mad i'm sure.