For throws, I use Toshiro Daigo's book Kodokan Judo Throwing Techniques published by Kodanasha International, Tokyo 2005. It specifically addresses some of the arcane points of Kodokan classification that distinguish what is considered one throw versus another. This book is mostly up to date. Is there a similar canonical resource that covers mat (pins, chokes, armlocks) techniques? For example, I was just informed that ude garami can be done against a straight arm. I previously would have called that an ude hishigi ude gatame.
The Kodokan's own video series Kodokan Judo Katame Waza: Various techniques and their names is probably the most authoritative resource. It demonstrates and lists the points of distinction of each technique and its common variations, divided into three sections:
The following books give detailed descriptions of katame-waza techniques:
- Judo Formal Techniques: A Complete Guide to Kodokan Randori no Kata, Tadao Otaki, Donn F. Draeger (1990)
- Best Judo, Isao Inokuma, Nobuyuki Satō (1986)
Alternatively, Isao Okano's acclaimed Vital Judo: Grappling Techniques describes which are applicable from which situation as opposed to listing techniques by type (e.g. joint locks, strangles, pins):
- Transition from Throws into Grappling Techniques
- Grappling-technique Attack Patterns
- Attacks from Above against on Opponent Lying Face Down
- Attacks from a Supine Position
- Attacks from a Prone Position
- Drawing Your Leg Free
- Genesis and Growth of the Seikijuku
Higher Judo: Groundwork, Moshe Feldenkrais (1952) also details ne-waza techniques from this perspective.
Notes on ude-garami:
Note that both texts listed above explicitly describe ude-garami as involving bending uke's arm at a near-90 degree angle (though the latter describes garami itself as referring to the entanglement of tori's arms in securing the lock).
Other volumes which do not go into as much detail (e.g. Techniques of Judo, Shinzo Takagaki, Hal Sharp (1957), Canon of Judo, Mifune (1958), Fighting Judo, Katsuhiko Kashiwazaki (1985)) also describe ude-garami as involving bending uke's arm before leveraging it to apply the lock.