1. Prepare the sweetened water .
2. Blanch almonds. Place half of them in a blender with water and blend to a smooth paste.
3. Strain mixture into a bowl through a double thickness of cheesecloth. Gather up corners of the cheesecloth and squeeze out every last drop of liquid; then discard residue.
4. Repeat this process with remaining almonds and the second quantity of water.
5. Break agar-agar in 1-inch sections and place in a saucepan with remaining water. Bring to a boil, stirring, and cook until agar-agar dissolves and begins to thicken. Then stir in almond liquid and cook 1 minute more.
6. Pour the mixture into a shallow rectangular pan. Let cool; then refrigerate until set. Cut in 1/2 inch cubes or diamond shapes.
7. Transfer to a deep serving dish.