Penetrating Enemy Lines and Capturing the Flag Stratego
Once the stronger side has established board domination, he is free to take as much time as he wants to organize his piece and prepare to penetrate enemy lines. When the material advantage is large, penetration is fairly simple—the stronger side simply marches in with his miner pieces, probes, and then mops up.
However, when the stronger side only has one remaining Miner and there are several possible enemy flag positions, the task of conversion becomes a much harder one. This is particularly true if the stronger side’s flag is exposed, meaning that he must play precisely so as not to allow any stray enemy pieces through.
Often, in such a case, the stronger side must rely on trapping techniques
and zugzwang techniques.
The zugzwang techniques here are not necessarily to win pieces outright, but rather to force the opponent to move an unmoved piece, revealing more information.
Probing in such cases is rarely an option, because the stronger side does not have many pieces left.
To show how it is possible to win a difficult case, we will examine an actual game played between two advanced Stratego players. The position was as follows: (Penetrating enemy lines)
In this position, Blue’s highest-ranking pieces are his Majors. All of his other pieces are ranked Lieutenant or below, and he has no Scouts (which, if Blue did have them, could easily get past Red’s board domination and capture his flag on e1).
Blue has three bombs remaining, and all of Blue’s pieces with the exception of his Majors are unmoved. At this point, Red must find a winning strategy that will capture Blue’s flag without allowing Blue any counterplay.
First, Red envisions all of the probable locations of the enemy flag.
Of course, there are other possible configurations, but these are the most probable. Here, we see clearly the danger for Red: since there are three remaining bombs to dismantle, he may waste his one remaining Miner on a bomb that doesn’t even cover Blue’s flag. Also, if Red simply marches in with his Captain and begins to capture enemy pieces (as many beginners would be tempted to do), he runs the risk of losing it to a bomb as well.
How, then, should Red go about converting his advantage? The trick is to eliminate the possibilities one by one, but without actually risking any Blue piece. A good first step would be for Red to realize that his Captain, since it is more powerful than any Blue piece except Blue’s Majors, could actually hold the Left Flank just as adequately as his General.
Red thus began with
1. Captain* b2-b3.
Blue will not move any of his unmoved pieces here, for two reasons: first, doing so would likely eliminate one of the four possible bomb formations described above, thus giving Red valuable information; second, any moved piece might be subject to later capture by Blue’s Captain, which could possibly march across the board and capture it with impunity. So, Blue played
1. . . . Major* h8-h9: