【Answer】Solution: (1) Because the color of the "unseen corner block" is the same as the corner block directly above it (based on Figure 2), which is yellow, and since yellow is opposite to white, the color of the unseen corner block that is in full contact with the table is white.
(2) The code for white is 1.

Therefore: The answer for this blank is 1.
9. (18 points) The international standard color configuration for a 3x3 Rubik's Cube: white top, yellow bottom, green front, blue back, orange left, red right. Now we define: white $=1$, yellow $=2$, green $=3$, blue $=4$, orange $=5$, red $=6$. A solved 3x3 Rubik's Cube is placed on the table (as shown in Figure 1), and today this Rubik's Cube is scrambled in a dynamic image manner, eventually becoming the state shown in Figure 2. At this point, 7 corner pieces can be seen in the image, so the color code of the corner piece that is completely in contact with the table and cannot be seen is $\qquad$ .