[en] Recently it has been shown that (π⁺, K⁺) reactions at around P_π ∼ 1GeV/c can be produced Λ hypernuclear states with large spin-polarization and spin-alignment. It is very interesting to produce spin polarized hypernuclei and to study asymmetry of weak decay of the polarized hypernuclei. We have a plan to produce polarized-Λ hypernuclei and to study asymmetry of the non-mesonic weak decay of the polarized-Λ hypernuclei. Asymmetry of non mesonic decay from the 1^- ground states of ¹²C and 5/2⁺ one of ¹¹B will be studied in the experiment. Here the ground state of ¹¹B is populated through proton decays (strong baryon decay) of 2⁺ states in ¹²C. Protons from non-mesonic decays are studied in coincidence with ¹²C(π, K⁺) reaction feeding the 1^- and 2⁺ states of ¹²C. Protons from non-mesonic decays of the ¹²C(1^-) and ¹¹B(5⁺/2) states are measured by two sets of ΔE·E counter telescopes which consist of 5mm plastic scintillator and segmented NaI scintillators. The PIK spectrometer, which has been constructed at the KEK K2 beam line, is used for the (π⁺, K⁺) reaction to produce hypernuclei. It's resolution is good enough to resolve the 1^- and 2⁺ states in ¹²C. The present plan is the first and important step for further study of weak and electromagnetic (magnetic moment γ decay etc.) process in hypernuclei