See also:ר [U+05E8 HEBREW LETTER RESH], ㄲ [U+3132 HANGUL LETTER SSANGKIYEOK], ㅋ [U+314B HANGUL LETTER KHIEUKH], ד [U+05D3 HEBREW LETTER DALET], ¬ [U+00AC NOT SIGN], and𠃍 [U+200CD CJK UNIFIED IDEOGRAPH-200CD]
The traditional account* holds that its its form is the outline of the back of the tongue blocking the throat when pronouncing /k/ (舌根閉喉之形), and Ledyard feels this consideration may have determined the form of simplified ག.
* Hunmin Jeongeum Haerye “Explanations and Examples of the Proper Sounds for the Instruction of the People” (1446), defining and explaining the script now known as 한글(han-geul, “Great script, Korean script”) in South Korea and 조선글(joseon-geul, “Korean script”) in North Korea.
In contemporary Korean, when ㄱ (g) is placed on the side, it curves as in the examples of 기 (gi), 길 (gil), 김 (gim), 경찰 (gyeongchal), 건강 (geon-gang), 건물 (geonmul), 게임 (geim), 개 (gae), 검정색 (geomjeongsaek), 안경 (an-gyeong), etc. However, when ㄱ (g) is placed on top or bottom, it retains its original look, as in the examples of 고려 (goryeo), 관심 (gwansim), 공부 (gongbu), 구상 (gusang), 권력 (gwollyeok), 금발 (geumbal), 금 (geum), 금융 (geumyung), 박다 (bakda), 먹다 (meokda), 죽다 (jukda), etc. This was done in the modern era to make the character look more balanced.