Before training can begin, the "gelanggang" must be prepared either by the guru or senior students in a ritual called "opening of training" ("upacara buka gelanggang" ). The purpose of this mandatory ritual is to clear the mind and to establish concentration and focus. In its traditional form, the ritual starts by cutting some limes into water and then walking around the area while sprinkling the water onto the floor. The guru walks in a pattern starting from the centre to the front-right corner, and then across to the front-left corner. They then walk backwards past the centre into the rear-right corner, across to the rear-left corner, and finally ends back in the centre. The purpose of walking backwards is to show respect to the "gelanggang", and any guests that may be present, by never turning one's back to the front of the area. Once this has been done, the teacher sits in the centre and recites an invocation so the space is protected with positive energy. From the centre, the guru walks to the front-right corner and repeats the invocation while keeping the head bowed and hands crossed. The right hand is crossed over the left and they are kept at waist level. The mantra is repeated at each corner and in the same pattern as when the water was sprinkled. As a sign of humility, the guru maintains a bent posture while walking across the training area. After repeating the invocation in the centre once more, the teacher sits down and meditates. Although most practitioners today train in modern indoor "gelanggang" and the invocations are often replaced with Islamic prayers, this ritual is still carried out in some form or another.