The Entrance Stone
Kerbstone 1 is the masterpiece of the Boyne Valley builders, and is the most recognisable symbol of prehistory in Ireland. I would have to add here that it is this stone which fired my imagination when I first came across it in History of Art at the age of 15; we had to learn to draw it freehand. I have been fascinated with it ever since.
The decoration consists of a large triple spiral engraved with double loops which fill the left side of the stone. The spirals rotate clockwise on the way to the centre and anti-clockwise moving away from the centre, a kind of ancient Irish Yin Yang. The triple spiral is echoed by another in the passageway, and yet another in the deepest recess of the chamber.
A group of chevrons (diamond shaped engravings) emerge from the left side of the spiral. The stone is divided by a vertical groove which marks the entrance position/azimuth of the sunrise on the solstice. The right side of the stone is composed of two bands of spirals which give way to a series of chevrons and arcs which move to the right.
There has been plenty of speculation about the meaning of this stone, and if you go on a tour at Newgrange, the guides will offer some of these. One of the most common explanations (and most simpleminded) is that the large triple spiral represents the three big mounds; the spirals on the right are some of the smaller mounds, and the wavy lines on the bottom represent the River Boyne. In this scheme, the rectangles, triangles and lozanges are the fields of the first farmers.
My own feelings about this symbol, having had a rubbing of it on my wall for many years, are that it is a lot more complex than that. My latest interpretation - since I took up music myself - is that it may bear some kind relationship to musical notation. Modern notation has a spiral in the 'treble' clef and the base clefs, while the chevrons appear close to where you might mark sharp or flat notes.
This brings us into deeper levels of symbolism, as music is closely related - indeed is formed from vibrations, and there are many, many New Agey theories about Newgrange. All energy moves in a spiral motion - there are many examples in nature such water going down a hole, tornadoes, cyclones, anti-cyclones, etc.
In years gone by people had to climb over the stone. The modern arrangement of cut limestone wings were installed during the rebuilding of Newgrange in the 1970's to save wear and tear on the stones. A huge number of people pass through this portal every year.