Taekwondo is an offensive and defensive Martial Art and Sport at the same time. So, yes we can block in taekwondo but allowed blocking techniques are depending on the different disciplines. Poomsae and Free Style Poomsae; Kyorugi and Hanbon, Dobon or Sebon Kyorugi (Step sparring, 1, 2 and 3) and Hochinsul, etc.