For the kata, see Gekisai Dai Ichi
Standard Bunkai
There are 5 standard bunkai for Gekisai Dai Ichi, some with a few variations. Note There are currently no photos/videos, I'll add some eventually.
Step back into hidari sanchin dachi blocking with hidari jodan age-uke, then step forward into migi hanzenkutsu-dachi punching migi jodan oizuki.
Note: You may step diagonally backwards, or move laterally to take yourself off-line. You can keep blocking with your right hand or drop it if you wish.
Suriashi on a on a 45-degree angle to the left, blocking with right handed gedan barai.
Follow with a right handed chudan punch to the side, shifting into zenkutsu-dachi and twisting your hips as you punch.
Variations: The attack can be a gedan oizuki instead of a gedan maegeri and in both versions the follow up punch is actually optional.
Block with a left handed chudan uke, suriashi to the right on a forward 45 degree angle standing in heiko dachi.
Gedan maegeri at the bladder/groin, land right foot forward in hanzenkutsu dachi or zenkutsu dachi. As you land perform a migi hiji-ate to the chest, follow with uraken to the face, then gedan barai to block the incoming punch. Follow with left handed chudan gyakuzuki
Block with migi chudan uke while doing a suriashi on a 45 degree angle forward and to the left.
Grab wrist with blocking hand, move in hip to hip, and shuto uchi across the attacker’s chest with the left hand.
Press with left arm and sweep the attacker’s right leg with the left leg.
Notes: When sweeping, stand hip to hip with your partner, get their centre of gravity backward using the shuto uchi (should be a heavy strike) and just after the strike, and lift their foot with the sweep (like passing a soccer ball), don't just kick it!
Block with migi chudan uke while performing a suriashi to the left on a 45 degree angle, finish in zenkutsu dachi.
Follow with double punch to the attacker’s side.