A whipping, snappy vertical backfist (BiinChoi) off of the round elbow (HyunJaang) is the hallmark of this martial combat sequence. The entire approach to opponent starts with the 1/2 combo, which closes the gap from the mid range. We then rain elbows, uppercuts, and finally a stunning backfist fitted directly into the eye socket. This sets us up for a shin stomp (or knee smash, which would be preferable) from the cross kick, bending your opponent over as they reel off balance and discombobulated from the whipping fist, making way for the cresent kick (BaiMuunToy, or door closing kick) to convert into an axe kick that strikes on the way down, ending it. If the cross kick isn't effective, because the opponent reels or steps backward, the following desperate straight line attacks (what most revert to as the simplest return fire, and the last place the brain would be able to calculate a target was would call for a direct line counter) would be cleared by the cresent kick to make way for the final sideways knee smash (turned from the cresent kick defense, this is much more severe of an injury than the pure hyperextension from the first one if it landed) with the follow up cross kick. This is a natural flow of kinetics from one strike to the next, varying side and line of attack enough to be powerful and effective without being complicated, as long as the strikes are LONG and CONNECTED, not choppy with spaces in between. The 1 of the 1/2 is the only strike on an upbeat (8th note), the rest are all on downbeats. Therefore, a 1/2-elbow-6-elbow-elbow-elbow-backfist breaks down musically and cueing to : AND =1(JAB), 1=2(CROSS), 2=LEAD ELBOW, 3=6 (REAR UPPERCUT), 4=LEAD ELBOW, 5=REAR ELBOW, 6=LEAD ELBOW, 7=BIINCHOI (WHIPPING BACKFIST). Counts sound like "and-1,2, 3, 4, 5, 6, 7". Practice, and then share, it makes for a sick sweat, as you can really lean into it! In HIPBOX, the 1/2/slip2X flow is sublime, classic, and not easy to do well. emphasize the lateral flexion of the spine using core musculature (obliques, erectors, multifidus) and a little bit of horizontal rotation to wind the punches up (transversus, obliques). The progression is to travel this forward and backward, even add a fast angled step or pivot, which you've learned in previous volumes. Enjoy!