After working with students for many years, I’ve noticed similarities in the way many of them approach and negotiate “Brush Knee” (aka lou-xi-ao-bu). This is true in Yang, SUN, and even Tai Chi Ruler (to name a few). I thought this might a good time to research and blog on “Brush Knee”, or as it is often known: Brush Knee Twist Step. Interestingly, this movement may have originally been known as “Walk obliquely with twist step”. I could find no documentation either way.
Anyone who has studied Tai Chi realizes, there are hundreds, if not thousands, of variations of most postures, including Brush Knee. There are even different interpretations in the same style depending on the lineage. In the Yang lineage that I teach, instead of “twist step”, the pivot on the back heel is called “closing the posture”. In some SUN lineages, there is no “twist step” per se; it is called “follow step”. SUN Brush Knee looks a lot like Yang style with some additional steps. For brevity (repetition, typing, and space), I will just refer to this movement as Brush Knee.
If you’ve seen any pictures of someone doing Tai Chi, they frequently are depicting a Brush Knee. The Brush Knee is even considered the quintessential and/or a fundamental posture in Tai Chi. This may be because it clearly emphasizes weight shifts along with unweighted side steps.
Important Points (non-combat):
When done correctly, Brush Knee improves your balance and your power. However, there is a risk of injuring your knee(s) if the twist step (or closing the posture) is not done correctly. When done incorrectly, you also lessen your power and put your other joints at risk. As one would expect, the “bent knee” must never “cave in” and timing is certainly important.
Your tailbone/pelvis needs to be tucked, while you sink slightly. Once you transfer the majority of your weight to the front, pick up your back toe and pivot on the heel. The back leg acts like a hinge from the heel to the Kua (body as a unit). When you turn the back foot in, you close the Kua on that side. Your Dantian faces front as your weight transfers forward (the direction you are going) and sinks, dropping the toe (flattening the back foot) to the ground. Be absolutely sure not to sink to the back foot.
The bent front knee stays bent, over the front foot. Relax, loosen the hips, neither knee straightens or locks.
Combat situations:
Almost everyone who does Tai Chi interprets a brush knee as a way to deflect a strike (front kick) to their knee. There are many choices (in a combat situation) as to what one does with the other hand. Face strike? Block? Let’s look a little closer at Brush Knee.
There are actually two parts to Brush Knee. The first would be neutralizing (often the left arm sweeping or coiling down). The second part is a strike, grab, and/or push with the right, if you are negotiating Brush Knee Left. Because the neutralizing is done in a circular motion, the movement is round and smooth. A Brush Knee gives you many martial or combat options including joint locking, kicking, unbalancing as well as pulling your opponent off his root and throwing him. Obviously, the point is to control your opponent after neutralizing his attack.
According to Master Jesse Tsao, author of 108 Answers to Tai Chi Practice, brush knee can be used to “defend against an incoming upper or lower kick”. You would then follow up with a counter-attack or strike. You do have a few options for your counter attack such as an arm joint lock, elbow strike (perhaps to his solar plexus), a throw after trapping the opponent’s leg, or as you might expect because the movement is “Brush Knee”, your can redirect that punch or kick and push your opponent back. For this last movement, Master Tsao suggests rounding one arm like a shield to protect your front while you sweep (or brush) away the incoming attack. Do not forget to step in to strike your opponent’s center with your other hand.
Brush Knee and Twist Step is useful in “street combat” according to Mr. M. The direction of your strike is “determined by the leading hand on the same side of the foot advancing the step”. Mr. M feels that angle is important and you should never step straight forward in front of your opponent. In order to use the movement skillfully, you should practice the “Brush Knee and Twist Step” on both the right and left.
Of note: when you are practicing, your movements are large, but in an actual combat situation, the motions are smaller and usually closer.
Typical errors most student’s make (combat or not):
The first tendency is to put the toe down too soon, before the weight has transferred to the front. Before pouring the weight, they drop the heel and toe down - “controlled falling”. The second most common error is to pull/transfer/pour the weight to the back foot when brushing the knee or at the end of the posture. Probably not a good idea, especially when an opponent is in front of you. Also not correct because Brush Knee is a forward (not retreating) movement.
A May 2023 study looked at neuromuscular control strategies in Brush Knee using a small group of Tai Chi practitioners. Half had knee pain and half did not. The researchers discovered that those with knee pain presented with some muscle imbalance and poor alignment of the knee with the toes in the forward motion. They also exhibited “rigid coordination strategies”. The researchers suggested training programs to modify “abnormal muscle synergy patterns” and to improve the alignment of the knee with the toes in the forward motion (lunge, although I dislike that word when referring to a Tai Chi movement).
For the readers who may be interested in reading more about biomechanics during Brush Knee:
Yu H, Wang J, Mao M, Song Q, Zhang C, Fong DTP, Sun W.Res Sports Med. 2021 Dec 26:1-10. doi: 10.1080/15438627.2021.2020788. Online ahead of print.PMID: 34957881
Tseng SC, Liu W, Finley M, McQuade K.J Electromyogr Kinesiol. 2007 Jun;17(3):372-80. doi: 10.1016/j.jelekin.2005.12.005. Epub 2006 May 24.PMID: 16723260
Chang T, Wang K, Huang S, Wang L, Zhang S, Niu W, Zhang M.Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2021 Feb 25;38(1):97-104. doi: 10.7507/1001-5515.202003003.PMID: 33899433 Chinese.
Li Y, Wang K, Wang L, Chang T, Zhang S, Niu W.Math Biosci Eng. 2019 Jan 30;16(2):898-908. doi: 10.3934/mbe.2019042.PMID: 30861671
For the readers who may enjoy viewing different variations of Brush Knee:
Quite a few of the linked articles in this blog also give examples of variations in Brush Knee.
Dan Djurdjevic in “Taijiquan application focus: brush knee” demonstrates some very interesting variations on the standard Brush Knee.
An interesting variation to view from a Shaolin Kung Fu Insights Studio: https://kungfuinsights.com/tai-chi-tips-7-brush-knee-press-forward/
https://www.oxfordtaichi.com/martial-application-brush-knee-twist-step/
I am sure I have only hit on a few of the numerous variations and techniques. It is always interesting to look at interpretations other than the one we know or teach.
Subscribe to receive my weekly blogs in your email.