The shield can be a physical item that is placed at the southern gate, and it can also, more importantly, be a magical tool which we cultivate through visualization and discipline. This shield is a semi-permeable barrier of etheric energy that we use for self-defense and cloaking magic.
Construction of the Magic Shield
The first thing to consider when building a magic shield is what you will be using it for. You will want to create a barrier that allows your own energy through unimpeded while offering you strong protection from outside influence. You may want to have a shield that surrounds you like a bubble (this is my personal space) or you may choose to have one that is tighter against your person, like armor. You will want your shield to be easy to "put on", so you may want to key it to a symbol that is easy to visualize.
One way to achieve this effect is through the use of pentagrams, triangles, and hexagrams (which are two triangles united). Pentagrams are used in magic whenever a portal needs to be cut. Pentagrams are charged with specific intent in order to let a certain energy or intelligence come through them. Examples of this include the use of pentagrams to call in intelligences during the LBRP, or the tracing or a pentagram over the body of the Priestess during the ceremony of Drawing Down the Moon. Pentagrams can be used in the visualization of your shield anywhere you would prefer to allow energy to pass through one-way.
|A powerful protective bindrune.|
When you have decided how you want to construct your shield begin its construction by drawing up power. Direct this power around you in the form and symbols you have decided to use. Hold the image of charging your shield firmly in your mind for as long as you can focus. With daily practice this will become easy to do. You are working to build a shield that you are so familiar with that you can call it up easily, yet has been charged regularly enough that it is strong and capable of defending you.
Defending you against what, exactly? Truthfully, it is a rare thing to do battle as a witch. If you have the misfortune of being in the midst of a "witchwar" then having a good shield is among the least of your worries. The shield is important when traveling astrally in flight, as you will sometimes encounter unsavory energies lurking about. In the work of Carlo Ginsburg there is discussion of the "Night Battles", which are common to those who travel out regularly. The Benedanti (witches and spirits working with the intent to bless) and the Maladanti (spirits working with the intent to harm) anciently do battle on the fields of the astral plane. The weapons of the witch (shield, sword, mask, and staff/spear) assist the walker between the worlds should she find herself in the midst of one of these battles.
The witches' shield is an advanced form of magic, and its use can be seen as a challenge to do battle by denizens of the otherworld. Remember that the shield is considered a weapon, albeit a defensive one. To put on your armor is a sign that you are looking for a fight. I recommend that you charge and visualize your armor daily in this realm, and I hope that you never have need of it in another.