It's difficult to read Robert Parish.

To begin with, he's 7 feet tall, so it's almost impossible for most people to look him straight in the eye. There's no clue there, anyway. Parish does virtually everything on the court with the same blank, expressionless gaze. He seems to have his sights set somewhere far off into the horizon.

"That's just his way," said Boston Celtic teammate M.L. Carr. "He's thinking about how he's going to dunk on your head or block your shot."

Parish has done both to the Bullets lately, a major reason they trail the Celtics, 3-1, in their best-of-seven National Basketball Association Eastern Conference semifinal playoff series. The Celtics can clinch the series with a victory Wednesday night in Boston.

After a poor game in the series opener, Parish came back with 17 points, 10 rebounds and five blocked shots in Game 2. In Games 3 and 4 at Capital Centre this weekend, he was a dominant player. In Saturday's 92-83 Boston victory he had 25 points, 13 rebounds and six blocked shots. He followed in Sunday's 103-99 overtime victory with 28 points, 15 rebounds and three blocks.

"The only guy we can't stop," said Bullet center Rick Mahorn, "is Robert Parish."

Like 6-11 teammate Kevin McHale, Parish has an awkward style that is effective, nevertheless. Offensively, his trademark is a smooth, arching jump shot he shoots anywhere on the floor from within 18 feet. He cocks the ball high over his head and releases it with his arms fully extended, so the ball is about 12 feet off the ground when he shoots. That makes it virtually impossible to block.

"No one has ever blocked it from in front," said Parish. "Some people have blocked it from behind or got it from the blind side, but that's the only way."

Parish is hardly a one-dimensional player on offense. If the defense takes the jumper away by crowding him, he'll put the ball on the floor and go to the basket with an assortment of hooks and dunks.

Some opponents say Parish moves his pivot foot and travels when he makes many of his moves, which gives him an unfair advantage. Maybe so, says Parish, "but it isn't traveling unless the officials call it."

They usually don't.

Parish has been called for traveling only five times in four games this series. "I don't think much about it," Parish said. "I just make my move."

Most 7-foot jump shooters, like Bill Cartwright of the New York Knicks, don't like to play inside, amid the elbows and pushing. Not so with Parish. He is just as effective inside as out. He simply takes what is offered and feels comfortable when the game gets rough.

"I like to mix it up," he said. "That's how you find out if your opponent has any heart." This entire series, Parish has been pushing, leaning and bumping bodies at both ends of the court.

"He's very aggressive, but no more so than you have to be to play that position," Mahorn said after Saturday's loss. "If you push him, he pushes back and he's trying to give more than he takes. But that's what you're supposed to do. He's strong and he's 7 feet tall, so that gives him a pretty good advantage, and he uses it."

Defensively, Parish is not a great leaper, but has excellent timing and is exceptionally quick. He has long arms and big hands and has become an effective shot-blocker.

Through their glory years, the Celtics never had a 7-foot center who could score easily, then go down to the defensive end of the floor and dominate there, too. They have that type of player in Parish, thanks to a gift from Golden State.

The Warriors felt they would be better off with 7-1 Joe Barry Carroll instead of sticking with Parish, who had averaged 14 points a game in four years with the team. Before the 1980 draft, the Warriors traded Parish and the third pick in the draft to the Celtics for the No. 1 pick. Boston took McHale with that third pick.

"I liked Parish's size and his mobility," said Boston General Manager Red Auerbach, "and I really wanted a 7-footer who could play. Sure, I could have taken Carroll, but this way I got Robert and McHale. I knew Robert had to be worked with to become the player we wanted, but (Coach Bill) Fitch liked him as much as I did, so we made the deal."

Shortly after the trade was made, Dave Cowens retired and Parish became the starting center.

"When I first came to Boston, it seemed that all they wanted me to do was rebound and block shots," Parish said. "but as I learned the system, they found out I could play and gained confidence in me. And now . . . "

Parish, 28, had a reputation at Golden State for being an introverted individualist, attributes that the Celtics don't usually want or seek. But Auerbach saw beyond the surface.

The Celtics also were impressed by Parish's loyalty. He played four years at Centenary in Shreveport, La., even though the school was on probation and Parish could have easily transferred.

In college, Parish had 50 points and 30 rebounds in one game, and in his senior year averaged 24 points and 18 rebounds. The Warriors made him the eighth player chosen in the 1976 draft.

"Robert has had stretches before like the one he is on now," said Larry Bird, who made only seven of 24 shots in the two games at Capital Centre this weekend. "Nothing he's doing now is surprising."

Parish said he is expecting Game 5 Wednesday to be just as tough and physical as the first four in the series. "They (the Bullets) aren't going to give up," he said. "I think the win they got in Boston in the second game was like a slap in the face to us and we were determined to go to Washington and establish ourselves. We want to end this series as soon as possible and the key is we have to establish our inside game."

That's what Parish is there for. That much you can read into his eyes.