Kosoto gari is a small reap applied to uke’s foot at the moment uke is stepping forward or backward. Timing is essential in this throw, along with good kuzushi so that uke’s posture is captured and he is unable to escape.
Ouchi gaeshi is a counter throw applied when uke is attacking with ouchi gari. There are several ways to apply the throw in different directions. The most basic and common method is explained here.
Osoto gaeshi is a counter throw to the always popular osoto gari attack. It is deceptively simple and is an important throw to learn early, maybe as your first counter throw. It is common to face weak osoto gari attacks when you are new and osoto gaeshi can be used to turn such attacks to your advantage. Knowledge of osoto gaeshi prevents your attacker from performing osoto gari without complete control because the position will be reversed and the attacker will be thrown instead.
Hiza guruma is the second throw in the standard teaching syllabus (gokyo no waza) of Kodokan Judo. It was a favorite throw of Dutchman Anton Geesink who was the first non-Japanese judo competitor to win the World Championships (1961) and Olympic Gold Medal (1964).
Kosoto gake is similar to kosoto gari, but is usually applied when uke has more weight on the foot you are attacking so it is not easy to reap the foot out. After hooking his leg, you can either lift uke and scoop the leg out or trap his leg and lean on him until he falls.
The basic principle in sukui nage is to use your hands to scoop uke’s legs out from under him as you rotate his upper body to the ground. The classic version described here is well suited for self-defense, but there are newer versions that are used in competition and randori. One such application is sometimes called te guruma but is classified as sukui nage by the Kodokan.
Ippon seoinage is a version of seoinage that was first recognized by the Kodokan as a distinct throw in 1997 after a review by the Kodokan Waza Research Institute. It conforms to the basic principle of seoinage – to load uke onto your back and throw him or her over the shoulder – but differs in application because of the position of the hands, both controlling one side of uke. Ippon seoinage is included in the first group of throws of the nage no kata where it is used to defend against a blow to the head. It is a very effective throw for self-defense since it can be performed without a judogi, but it is also quite popular in free practice and competition.
Obi otoshi is very similar to sukuinage (scooping throw) in the foot position and the direction of the throw. The difference is in the hand position. One hand grabs the front of the belt in obi otoshi, instead of both hands grabbing the legs of uke. Because grabbing the belt is restricted under competition rules and grabbing the front of the belt gives away your intentions, there are seldom opportunities to apply this throw.
Morote gari is a hand throw that involves grabbing both of your partner’s legs and reaping them out. It has been officially recognized by the Kodokan as a judo throw since 1982 and had been used in competition for years, but under current IJF competition rules (as of 2014) this technique is no longer permitted. It is called a double leg takedown in wrestling.
Tai otoshi is a hand throw that should generate a lot of power with very little contact. It can create one of the hardest falls in judo, yet it relies on timing and kuzushi rather than lifting. The power comes from a fast rotating action that drives uke right into the mat. It is a very common throw, but one which must be studied thoroughly to have any chance of using it successfully on a resisting opponent.