Basically, if you work on a technique of your own (and it does not involve arm or leg locks, or submission tactics etc) i.e. if it is a basic "throw" or "takedown", are they legal to use in competition?
Judo competition is not graded on the name of the technique you do. It's graded on whether you throw the opponent on their back, pin them, strangle them, put them in an armlock, or break the rules.
So yes, you can use improvised or "unnamed" throws, or non-standard pins and so on, as long as it's not specifically forbidden.
But if you've never trained judo, nor wrestling, nor Brazilian jiu-jitsu or shuai jiao or Bokh, then it's unlikely (but not impossible) that your self-trained technique is as unique or effective as you think it is.
Until recently, yes, throwing the opponent with control and speed onto their back was the criteria for scoring a point, whether or not the technique had a classification in the Kodokan syllabus. As such, historically innovative techniques such as:
As well as makikomi variants of throws (and common kaeshi counters to throws) have even been added to the syllabus due to their prominence. Other innovative competition techniques exist and have been used to score such as:
- "Maruyama special" (no longer scoring due to the leg grab)
- "Laats dive-in"
- "front" uchi-mata
- "reverse" seoi-nage (now banned)
- "sambo" seoi-nage / "drop" kata-guruma
- Korean tai-otoshi
While many of these may be variants of existing techniques, they are distinct enough in their entries/execution to have earned their own names in the judo community.
In 2022 the IJF introduced the following rule however:
A judo technique which is present in the judo accepted repertoire (gokyo) must be identified. Just landing and rolling over and falling on the side/back in the process of the contest, without applying a clear technique, is not enough to score. It must be within the bounds of the published list of Kodokan judo techniques.
- IJF Sport and Organisation Rules (SOR) - 24.04.2023 - ENG
No score for counter techniques where the initial attack is rolled to the back, towards the counterattacking or defending judoka. There has to be a difference between the correctly applied counter-technique and falling on the mat and turning/rolling over the opponent. In the case of correct technique like uchi-mata-gaeshi, harai-goshi-gaeshi or hane-goshi-gaeshi, but also uchi-mata-sukashi, ura-nage, yoko-guruma, tani-otoshi, ko-soto-gari and ko-soto-gake, if we can identify the technique with a proper 90° landing there will be a score. In the case of a front landing or one less than 90°, the rolling to the back will be considered as transition to ne-waza.