Double and Twin definitions

Question

Could someone give me definitions for

1) Double (Doo) - eg. ??

2) Twin (Sang) - eg. twin forearm block, Dangun

In ITF Taekwon-Do?

Note: I'm struggling to understand the difference, relating to a yellow belt student.

Answer 1

• A twin block is where the arms are apart (for instance, Sang Palmok Makgi, or Sang Songkal Makgi).
• A double block is where the arms are 'together' (for instance, Doo Palmok Makgi, or Doo Bandalson Makgi).

For Sang Palmok Makgi (twin forearm block) or Sang Songkal Makgi (twin knifehand block), one arm is at the mid-section, with the elbow roughly level with the bottom of the ribs and the hand level with the shoulder; the second arm is above the head (in a similar position to a rising block). The final hand positions are different (closed fist for the former, open hand for the latter), but the arms are apart.

For Doo Palmok Makgi (double forearm block), one hand is in a middle block position (elbow roughly level with the bottom of the ribs and hand level with the shoulder) and the other hand is level with the elbow of the first hand. For Doo Bandalson Makgi (Double arc-hand block), the two hands face palm outwards at roughly shoulder height. Thus, the arms are together.

Answer 2

Perhaps the criterion is to do with whether or not the arms swing into the block together from the same side of the body?

Double forearm block (doo palmok makgi) has both arms swing around the hips together, while the double arc-hand block (doo bandalson makgi) has the arms/hands start near one shoulder then swing together into the block.

Twin blocks are either moving in different directions (sang palmok makgi), or coming in from opposite sides (e.g. twin palms).

Answer 3

Based on this website:

A twin block is a defence against two attackers, and a double block is a defence against one attacker.

Twin Block (blocking two attackers at once)

Double Block (two blocks for one attacker)

Answer 4

I'll ask my instructor- it seems that he told me the difference once but I can't remember exactly how he worded it-- maybe a "twin" is both hands in same position and a double has a different position for each arm? We call the first move of Dan Gun a "double knifehand block", which is against a single attacker, and move 13 of Do San a "twin outer forearm block", which I was taught was to prevent a choke grab also by a single attacker. I'll ask next week- sorry I can't be more definitive.