These tactics are also shown in the alternate strategies video.
For this strategy you can use the rifle or pistols. The rifle does more damage at long range, but this is more likely to cause Takamoto to retaliate. If you're using the rifle, you'll see a red targeting reticle (above). Pistols have a shorter range, so you won't see a red reticle, but the reticle should turn from white to gray (last two screenshots below). Then, while you won't be hitting him dead on, some of your shots should connect.
He may change his position a little from time to time, and occasionally your shots will stop doing damage for no apparent reason. When this happens, return to normal view, move Lara bit to compensate, and try again.