Both are Taisabaki images... above
This is Fudo Kamae... above
Now it is very important to realize the differences in how Ichiminji no Kamae is applied & how Fudo Kamae of Black Dragon Ninjutsu is applied. Fudo Kamae is merely a platform for striking techniques, Black Dragon Ninjitsu uses explosive power, the snapping of the hips (called Fajing in Kung-fu, Chinkuchi in Okinawan Karate), thrust of the arm and transfer of body wieght along the knees to generate an explosive thrust into the target. The application of Ichimonji no Kamae is more often then not similar to the application of Kokutsu Datchi of Karate.
Fude Kamae is a fluid platform used to teach principles like balance, movement and positioning. They are similar in principle but not application the generation of power comes from the movement of the body. Strikes in Black Dragon Ninjitsu from Fudo Kamae are similar to a whip snapping and once the concept is learned, the Black Dragon Ninjitsu disregards the posture for the principles of balance, footwork and movement existing in the kinetics of the moment.
Comparing the two is like comparing apples to oranges... Omoto Ryu Jujutsu/Taijutsu (we should I know by now I used the "i" and "u" interchangably in "jutsu/jitsu") is very fluid almost Aikido-like in application but also far more aggressive in application. As in Karate, Budo Taijutsu, Aikido, Judo & Jujitsu taisabaki plays a big part, because you are not just moving your knees but positioning your body to avoid and even counter your opponent's action. However, to generate power you must also apply Koshi-Waza (Hip Technique) also called Fajing in Chinese arts & Chinkuchi in Okinawan Karate. This is the concept of explosive power being delivered behind one's strikes and not merely "leaning" into the strike.
The difference in power of impact as well as the ability to change targets is very simple. The passive raised arm of taisabaki exists only to show the potential range of one's strikes while moving away, around or closer to one's opponent. Allow me to show you exactly what I am referring to.
Here is an online course from a Bujinkan Dojo, I grabbed it to highlight the differences here... That said I'm talking about technical thinking and not the individual here. The principles are sound, the execution for his art is fine but to my level of thinking no so much...
Compare this to say Karate were here we see in a Tournament a person the person on the right using a much larger and more telegraphed lunge strike & it is countered by stepping back and executing a faster reverse punch to the chin. The Winning Karateka also used their positioning on the inside of the attacker's guard to position themselves for the strike. The fact that the Losing Karate was also in a position to counter with a reverse punch is still there.
Now just so you understand what everything is we have this image, the term centerline is found in Wing Chun and Jeet Kune Do it refers to an imaginary line from the area above the upper lip & below the nose and goes to the groin passing through the solar plexus/diaphragm. I passing along a path that includes almost all vital areas on the torso.
Here were see the idea of offsetting or aligning to the strike the centerline area and targets like the chin, nose, throat, solar plexus & diaphram, the floating ribs, various organs along the belly and the groin. If the fighters were to stand square or even off set such as above they create a "triangle" that reveals the essential angles for striking.
Following the triangle we can see that both hands are equal distance from the centerline and our "triangle" is created. The base of the triangle is the line of intersecting for defense while the two sides are paths to strike (excluding the potential for hooking strikes) for arguments sake. By standing offset the trangle changes to place on fist closer to the target area then the other.
As you can see here the left hand (ok its circle but it represents a hand) is closer to the target then the right. This is the position the Karate fighter used to deliver a reverse punch for the win in the above video. If each one is standing at an angle the triangle changes.
Here see this triangle elongated and this is looking at the square up for two orthodox fighters (meaning two right handed boxers). The range of the reverse punch is extended and less lightly to deliver a blow, were as the lead hand is capable of delivering jabs and hard leads to the opponent. Something the passive lead hand floating represents in Taisabaki.
Breakdown the Ichimonji no Kamae and the inside 45-degree angle places you in danger of a reverse hand strike. You are literally lining yourself up for the reverse hand strike.
This is just to point out both that the Taisabaki image is not Ichimonji no Kamae and that the principle foundation of Ichimonji no Kamae is not something endorsed by Black Dragon Ninjitsu on a technical level.